Cyclical heat stress during lactation influences the microstructure of the bovine mammary gland.

This study aimed to evaluate the impact of heat stress on mammary epithelial cell (MEC) losses into milk, secretory mammary tissue structure, and mammary epithelial cell activity. Sixteen multiparous Holstein cows (632 ± 12 kg BW) approximately 100 d in milk housed in climate-controlled rooms were paired by body weight and randomly allocated to one of 2 treatments, heat stress (HS) or pair feeding thermoneutral (PFTN) using 2 cohorts. Each cohort was subjected to 2 periods of 4 d each. In period 1, both treatments had ad libitum access to a common total mixed ration and were exposed to a controlled daily temperature-humidity index (THI) of 64. In period 2, HS cows were exposed to controlled cyclical heat stress (THI: 74 to 80), while PFTN cows remained at 64 THI and daily dry matter intake was matched to HS. Cows were milked twice daily, and milk yield was recorded at each milking. Individual milk samples on the last day of each period were used to quantify MEC losses by flow cytometry using butyrophilin as a cell surface marker. On the final day of period 2, individual bovine mammary tissue samples were obtained for histomorphology analysis, assessment of protein abundance, and evaluation of gene expression of targets associated with cellular capacity for milk and milk component synthesis, heat response, cellular proliferation, and autophagy. Statistical analysis was performed using the GLIMMIX procedure of SAS. Milk yield was reduced by 4.3 kg by HS (n = 7) compared with PFTN (n = 8). Independent of treatment, MEC in milk averaged 174 cells/mL (2.9% of total cells). There was no difference between HS vs. PFTN cows for MEC shed or concentration in milk. Alveolar area was reduced 25% by HS, and HS had 4.1 more alveoli than PFTN. Total number of nucleated MEC per area were greater in HS (389 ± 1.05) compared with PFTN (321 ± 1.05); however, cell number per alveolus was similar between groups (25 ± 1.5 vs. 26 ± 1.4). There were no differences in relative fold expression for GLUT1, GLUT8, CSN2, CSN3, LALBA, FASN, HSPA5, and HSPA8 in HS compared with PFTN. Immunoblotting analyses showed a decrease abundance for phosphorylated STAT5 and S6K1, and an increase in LC3 II in HS compared with PFTN. These results suggest that even if milk yield differences and histological changes occur in the bovine mammary gland after 4 d of heat exposure, MEC loss into milk, nucleated MEC number per alveolus, and gene expression of nutrient transport, milk component synthesis, and heat stress related targets are unaffected. In contrast, the abundance of proteins related to protein synthesis and cell survival decreased significantly, while an upregulation of proteins associated with autophagy in HS compared with PFTN.

Ileal phosphorus digestibility of soybean meal for broiler chickens remains consistent across institutions in a collaborative study regardless of non-phytate phosphorus concentration in the pre-experimental starter diet.

The same experimental protocol was used in 4 institutions to evaluate the impact of non-phytate phosphorus (nPP) concentration in the starter diet on regression method-derived ileal P digestibility of soybean meal (SBM) during the subsequent grower phase. A total of 1,536 Ross 308 male broiler chickens on d 0 post hatching were allotted to 2 pre-experimental starter diets that contained 3.5 or 4.5 g nPP/kg (96 replicate cages per diet, 8 birds per cage) for 18 d. Subsequently, 576 birds from each starter diet were selected and allocated to 3 experimental semi-purified grower diets containing 400, 510, or 620 g SBM/kg (32 replicate cages per diet, 6 birds per cage) for 3 d until collection of ileal digesta. Statistical analysis was conducted as a randomized complete block design with the starter period as whole plot and the grower period as split-plot. The only significant 2-way interaction was between grower diet and experimental institution (P < 0.05) on BW gain and gain to feed ratio. The main effect of institution and grower diet impacted (P < 0.05) feed intake, the digestibility of DM, P, and calcium, and disappearance of inositol hexakisphosphate (InsP6) in the grower diets. Birds fed the 3.5 g nPP/kg starter diet had lower (P < 0.05) BW gain and feed intake during the grower period, but presented higher (P < 0.05) digestibility of P and disappearance of InsP6 compared with the birds that were fed the 4.5 g nPP/kg starter diet. Regression method-derived ileal P digestibility of SBM was determined to be 46 or 42% for the respective 3.5 or 4.5 g nPP/kg pre-experimental starter diet and was not affected by the nPP concentration or by the institution. In conclusion, the experimental protocol used in the current study resulted in similar estimates across multiple institutions and is thus endorsed for future application in studies that aim to expand the database of digestible P content in plant source feed ingredients.

Relationships Between Gastrointestinal Permeability, Heat Stress, And Milk Production in Lactating Dairy Cows.

Heat stress (HS) is a global issue that decreases farm profits and compromises animal welfare. To distinguish between the direct and indirect effects of HS, 16 multiparous Holstein cows approximately 100 d in milk were assigned to one of 2 treatments: pair fed to match HS cow intake, housed in thermoneutral conditions (PFTN, n = 8) or cyclical HS (n = 8). All cows were subjected to 2 experimental periods. P1 consisted of a 4 d thermoneutral period with ad libitum intake. During P2, the HS cows were housed in cyclical HS conditions with a temperature humidity index (THI) ranging from 76 to 80 and the PFTN cows were exposed to a constant THI of 64 for 4 d. DMI of the PFTN cow was intake matched to the HS cows. Milk yield, milk composition, rectal temperature, and respiration rate were recorded twice daily, blood was collected daily via a jugular catheter, and cows were fed twice daily. On d 3 of each period, Cr-EDTA and sucralose were orally administered and recovered via 24 h total urine collection to assess gastrointestinal permeability (GIP). All data were analyzed using the GLIMMIX procedure in SAS. The daily data collected in P1 was averaged and used as a covariate if deemed significant in the model. HS decreased voluntary intake by 35% and increased rectal temperature and respiration rate (38.4 vs 39.4°C and 40 vs 71 respirations/min, respectively). HS reduced dry matter intake (DMI) by 35% which accounted for 66% of the decrease in milk yield. The yield, and not concentration, of milk protein, fat, and other solids were lower in the HS cows on d 4 of P2. Milk urea nitrogen (MUN) was higher and plasma urea nitrogen (PUN) tended to be higher on d 3 and d 4 of HS. Glucose was 7% lower in the HS cows and insulin was 71% higher in the HS cows than the PFTN cows on d 4 of P2. No difference in lipopolysaccharide binding protein (LBP) was observed. HS cows produced 7 L/d more urine than PFTN cows. No differences were detected in the urine concentration or percentage of the oral dose recovered for Cr-EDTA or sucralose. In conclusion, HS was responsible for 34% of the reduction of milk yield. The elevated MUN and the tendency for elevated PUN indicate a whole-body shift in nitrogen metabolism. No differences in GIP or LBP were observed. These results indicate that, under conditions of this experiment, activation of the immune system by gut derived lipopolysaccharide was not responsible for the decreased milk yield observed during HS.

Effect of day-old chick weight on the response of broilers to high doses of exogenous phytase.

A total of 360 Ross 708 male broiler chicks were used in an 8 treatment and 9 replicate cage study to explore the influence of day-old chick weight on the efficacy of exogenous phytase. Treatments were arranged as a 2 × 4 factorial with the factors being diet (a positive (PC) and negative control (NC) varying in nutrient density fed without or with 2 concentrations of exogenous phytase) and chick weight (light; <38.5 g or heavy; >42 g). Chicks were sourced from the same breeder flock, with light and heavy chicks being selected from the naturally occurring heterogeneity in the population. The diets were corn-soybean meal based and the PC was formulated to meet the nutrient requirements of male broiler chicks. The NC was formulated to contain 120 kcal/kg, 0.5, 0.18, and 0.18% less apparent metabolizable energy (AME), crude protein (CP), calcium (Ca), and phosphorus (P), respectively, than the PC. Amino acid (AA) density in the NC was also reduced in line with the reduction in CP and the manufacturers' recommendations for the effect of phytase on amino acid digestibility. Phytase at either 1,000 FYT/kg or 3,000 FYT/kg was added only to the NC to create a total of 4 diets. Water and mash feed were available ad libitum and were offered to 8 replicate cages, each containing 5 chicks. The experiment was conducted over a period of 3 wk and diets were offered in 2 phases (starter from d 1 to 10 and grower from d 11 to 21). Growth performance was monitored at the end of each diet phase and on d 21 ileal digesta were collected for estimation of apparent digestibility of energy (DE), nitrogen (N), Ca, P, dry matter (DM), and AA. There were no statistically significant interactions between diet and day-old chick weight for any of the measured parameters. Light chicks had significantly lower weight gain (approx. 5%) at both d 10 and d 21 compared with heavy chicks. This effect was principally associated with reduced feed intake and there was no significant effect of chick weight on feed conversion ratio (FCR). Chick weight had no effect on ileal nutrient digestibility. The reduction in nutrient density from the PC to the NC generated a significant reduction in weight gain (around 12%) and a significant increase in FCR (1.68 vs. 1.83). This effect was associated with a significant reduction in ileal DE (approximately 150 kcal/kg) and in the digestibility of several AA. Exogenous phytase significantly increased weight gain, reduced FCR and generated a significant increase in the ileal digestibility of energy, N, P, and several AA. Although chick weight and diet did not interact statistically, heavy chicks benefited more than light chicks from high doses of exogenous phytase across almost all measured end points which was confirmed by regression analysis. In conclusion, light chicks have inferior performance outcomes than heavy chicks principally because of reduced feed intake, but putatively not in digestive capacity per se. Exogenous phytase is effective in improving performance and nutrient digestibility in nutrient deficient diets. The effect of chick weight per se, and also breeder flock age, on the utility of supra-nutritional inclusion concentrations of exogenous phytase warrants further study.

Research Note: Relative bioavailability of zinc in zinc hydroxychloride for chicks.

A chick assay was conducted to determine the effects of Zn source on performance and to establish a Zn relative bioavailability value (RBV) for a new source of Zn hydroxychloride. In the assay, 8-day-old chicks were fed a Zn-deficient soy protein concentrate diet supplemented with 0, 7, and 15 mg Zn/kg from feed grade ZnSO4 monohydrate for 14 d to establish a standard response curve. The same basal diet was supplemented with 3, 7, and 10 mg Zn/kg from a new Zn hydroxychloride (SAMZn). A second source of Zn hydroxychloride (IBZn) was supplemented at 10 mg Zn/kg as a direct comparison to the highest level of SAMZn. Weight gain increased (P < 0.05) with increasing Zn level, regardless of source. Weight gain of chicks fed 7 mg Zn/kg from SAMZn was not different (P > 0.05) from chicks fed 15 mg Zn/kg from ZnSO4. Weight gain was not different (P > 0.05) when comparing the 2 sources of Zn hydroxychloride supplemented at 10 mg Zn/kg. Tibia ash Zn and total tibia Zn were increased (P < 0.05) by all Zn sources and responded linearly (P < 0.05) to Zn supplementation from ZnSO4 and SAMZn. Total tibia Zn concentration was not different (P > 0.05) for chicks fed 10 mg Zn/kg from either source of Zn hydroxychloride. Multiple linear regression of total tibia Zn on supplemental Zn intake (R2 = 0.95) resulted in a RBV of 115% for SAMZn compared with ZnSO4 (set at 100%). The RBV of SAMZn was higher (P < 0.05) than ZnSO4. In conclusion, relative bioavailability of Zn (based on tibia Zn) in Zn hydroxychloride from SAMZn was higher than feed grade ZnSO4 based on multiple regression slope-ratio analysis and was similar to that of IBZn Zn hydroxychloride based on tibia Zn responses to 10 mg/kg supplemental dietary Zn.

Determination of TMEn, standardized amino acid digestibility, phosphorus digestibility, and phosphorus bioavailability in conventional and reduced phosphorus distillers dried grains with solubles.

The TMEn, amino acid (AA) digestibility, and P availability in 2 conventional corn distillers dried grains with solubles (C-DDGS1 and 2; 0.86 to 1.14% P, DM basis) and reduced phosphorus DDGS (RP-DDGS; 0.39% P) were evaluated. The TMEn of C-DDGS1 and 2 and RP-DDGS were determined in Experiment 1 using conventional adult Leghorn roosters, while standardized AA digestibility was determined in Experiment 2 using cecectomized roosters. Apparent ileal digestibility (AID) of P at different Ca levels was determined using precision-fed (crop intubation) broiler chickens in Experiments 3 and 4. The AID and total tract retention of P in C-DDGS2 were evaluated in Experiment 5 using ad libitum-fed broilers. Phosphorus bioavailability in C-DDGS2 relative to KH2PO4 based on bone ash was determined in Experiment 6. Experiments contained 4 to 5 replicates per treatment. In Experiment 1, the TMEn of C-DDGS1 and RP-DDGS was 3,428 and 2,840 kcal/kg, respectively (DM basis). In Experiment 2, there were no differences (P > 0.05) in rooster AA digestibility values between C-DDGS1 and RP-DDGS. In Experiment 3 with precision-fed chicks, AID of P in C-DDGS1 and RP-DDGS was 81 and 59%, respectively; there was no effect (P > 0.05) of increasing dietary Ca level from 0.04 to 1.0% for C-DDGS1 or reducing Ca from 1.5 to 1.0% for RP-DDGS. The AID of P in precision-fed chicks for C-DDGS2 in Experiment 4 was 48 and 80% at 1.3 and 0.3 Ca:total P ratios, respectively (P < 0.05). In Experiment 5, AID of P in C-DDGS2 at Ca:total P ratios of 1.3 and 2.5 was 63 and 42%, respectively, in precision-fed chicks. Regression of bone ash content (mg/tibia) on supplemental P intake in Experiment 6 yielded a P bioavailability of 61% relative to KH2PO4 for C-DDGS2. In conclusion, total and digestible P content in RP-DDGS was greatly reduced compared with C-DDGS, and the digestibility and bioavailability of the P in C-DDGS was affected by type of experimental assay and dietary Ca level.

Effects of adaptation diet and exogenous enzymes on true metabolizable energy and cecal microbial ecology, short-chain fatty acid profile, and enzyme activity in roosters fed barley and rye diets.

Three experiments evaluated effects of adaptation diet and exogenous ß-glucanase and xylanase on TMEn of barley and rye. Single Comb White Leghorn roosters were fed adaptation diets based on corn/soybean meal (SBM), barley/SBM with and without ß-glucanase, or rye/corn/SBM with and without xylanase for 4 wk. In Experiments 1 and 2, after the adaptation period, TMEn was determined using a 48 h precision-fed rooster assay for 100% barley or 100% rye diets with or without ß-glucanase or xylanase, respectively. Experiment 3 consisted only of feeding adaptation diets for 4 wk. Cecal samples were collected at the end of experiments for microbial ecology, short-chain fatty acid (SCFA) profiles, and enzyme activity analyses. In Experiments 1 and 2, ß-glucanase increased (P < 0.05) TMEn of barley, and there was no significant effect of adaptation diet on TMEn values. Total cecal Eubacteria and Ruminococcaceae were decreased (P < 0.05) and Escherichia coli were increased (P < 0.05) at the end of the TMEn assay compared with the end of the adaptation period (with no TMEn assay). There was a large decrease (P < 0.05) for most cecal SCFA at the end of the TMEn assay compared with the end of the adaptation period. Both cecal ß-glucanase and xylanase activity were increased for birds fed adaptation diets containing the respective enzyme. In Experiment 3, there were no consistent effects of adaptation diet on cecal microbial profiles or SCFA but cecal ß-glucanase activity was increased (P < 0.05) by exogenous ß-glucanase for barley and cecal xylanase activity was increased (P < 0.05) by exogenous xylanase for rye. Overall, the results indicated that TMEn of barley was increased by exogenous ß-glucanase, adaptation diet did not significantly influence the TMEn response to the dietary enzymes, and cecal fermentation (based on cecal SCFA) was greatly reduced by the TMEn assay. Cecal ß-glucanase and xylanase activity, however, were often increased by feeding high barley and high rye diets containing exogenous enzymes.

Nutritional evaluation of soybean meals varying in particle size.

The objective of this study was to evaluate the effect of varying soybean meal (SBM) particle sizes on nutritional value of the SBM. Seven samples of dehulled solvent-extracted SBM from the same batch were ground to varying mean particles of <386, 466, 809, 1,174, 1,577, 2,026, and 2,321 µm. Two precision-fed rooster assays (crop intubation with 25 g of SBM followed by 48 h total excreta collection) were performed to determine TMEn and standardized amino acid (AA) digestibility. There were no significant differences for TMEn among SBM samples, and there was also no consistent significant effect of particle size on standardized AA digestibility. In addition to the 2 precision-fed rooster assays, a 21 d broiler chick trial was conducted using corn-SBM based diets using 4 diets that differed only in the mean particle size of SBM (466, 809, 1,174, or 1,577 µm), being fed from 2 to 23 d of age. Chicks fed diets containing 809 or 1,174 µm SBM had increased (P < 0.05) weight gain compared with chicks fed the diet containing 466 µm SBM, and chicks fed diets containing 1,174 or 1,577 µm SBM had increased (P < 0.05) feed efficiency compared with chicks fed the diet containing 466 µm SBM. The diet containing 466 µm SBM yielded the highest (P < 0.05) AMEn and total tract P retention. Ileal P digestibility and standardized AA digestibilities did not differ among treatments. Relative gizzard weight (percent of body weight) was increased (P < 0.05) by the 2 largest SBM particle sizes. The results from these 3 experiments showed that increasing SBM particle size may be beneficial to broiler growth performance and may increase gizzard size but had no consistent significant effect on ME, AA digestibility, or P digestibility/retention.

Quantification of secretory IgA and mucin excretion and their contributions to total endogenous amino acid losses in roosters that were fasted or precision-fed a nitrogen-free diet or various highly digestible protein sources.

The objective of this study was to quantify total secretory IgA (sIgA) and mucin excretion via excreta in roosters fed diets containing highly digestible protein sources and to determine their proportional contributions to total endogenous amino acid (AA) losses. Precision-fed rooster assays with 24 h excreta collections were conducted using conventional White Leghorn roosters (4-8 roosters per treatment). In Experiment 1, roosters were fasted or precision-fed 30 g (crop intubation) of a nitrogen-free (NF) or semi-purified diet containing 10% casein. Roosters in Experiment 2 received a NF or semi-purified diet containing either 10% casein, 17% whole egg, 10% egg white, 9.8% soy protein isolate, 10.2% chicken breast meat, 11.2% spray-dried animal plasma (SDAP), or an AA mixture containing the same AA as casein. A Latin square design was used in Experiment 3, where roosters received NF or semi-purified diets containing either 10% casein, 17% whole egg, or 9.6% of a crystalline AA mixture to evaluate both diet and individual bird effects. In Experiment 1, mucin excretion did not differ (P > 0.05) among treatments; however, total sIgA excretion was lower for fasted birds, intermediate for the NF diet, and highest for casein (P < 0.05). Total endogenous AA losses (proportion of the total) from sIgA were higher for roosters fed casein, whereas mucin contributions were higher for fasted roosters (P < 0.05). In Experiment 2, sIgA excretion did not differ (P > 0.05) among treatments; however, mucin excretion was reduced for NF, whole egg, egg white, and chicken breast compared with casein and SDAP. In Experiment 3, sIgA and mucin excretion did not differ (P > 0.05) among treatments; however, sIgA excretion differed among individual roosters (7-27 mg/24 h; P < 0.05). Overall, fasting reduced sIgA excretion and sIgA and mucin excretion were affected by dietary protein source. Further, roosters excreted a substantial amount of sIgA, and sIgA and mucin were considerable contributors to total endogenous AA losses.

Disparities in Deceased Donor Kidney Offer Acceptance: A Survey of Canadian Transplant Nephrologists, General Surgeons and Urologists.

Background: Significant variability in organ acceptance thresholds have been demonstrated across the United States, but data regarding the rate and rationale for kidney donor organ decline in Canada are lacking. Objective: To examine decision making regarding deceased kidney donor acceptance and non-acceptance in a population of Canadian transplant professionals. Design: A survey study of theoretical deceased donor kidney cases of increasing complexity. Setting: Canadian transplant nephrologists, urologists, and surgeons making donor call decisions responding to an electronic survey between July 22 and October 4, 2022. Participants: Invitations to participate were distributed to 179 Canadian transplant nephrologists, surgeons, and urologists through e-mail. Participants were identified by contacting each transplant program and requesting a list of physicians who take donor call. Measurements: Survey respondents were asked whether they would accept or decline a given donor, assuming there was a suitable recipient. They were also asked to cite reasons for donor non-acceptance. Methods: Donor scenario-specific acceptance rates (total acceptance divided by total number of respondents for a given scenario and overall) and reasons for decline were determined and presented as a percentage of the total cases declined. Results: In all, 72 respondents from 7 provinces completed at least one question of the survey, with considerable variability between acceptance rates for centers; the most conservative center declined 60.9% of donor cases, whereas the most aggressive center declined only 28.1%, P-value < .001. There was an increased risk of non-acceptance with advancing age, donation after cardiac death, acute kidney injury, chronic kidney disease, and comorbidities. Limitations: As with any survey, there is the potential for participation bias. In addition, this study examines donor characteristics in isolation, however, asks respondent to assume there is a suitable candidate available. In reality, whenever donor quality is considered, it should be considered in the context of the intended recipient. Conclusion: In a survey of increasingly medically complex deceased kidney donor cases, there was significant variability in donor decline among Canadian transplant specialists. Given relatively high rates of donor decline and apparent heterogeneity in acceptance decisions, Canadian transplant specialists may benefit from additional education regarding the benefits achieved from even medically complex kidney donors for appropriate candidates relative to remaining on dialysis on the transplant waitlist.

Contexte: Une importante variabilité a été observée aux États-Unis dans le seuil d'acceptation des organes. Au Canada, on manque de données sur le taux de refus des donneurs de reins et sur les raisons qui expliquent ce refus. Objectifs: Examiner la prise de décision quant à l'acceptation ou non d'un donneur de rein décédé dans une population de professionnels de la transplantation canadiens. Conception: Un sondage exposant des cas théoriques de plus en plus complexes de donneurs de reins décédés. Cadre: Des néphrologues, urologues et chirurgiens canadiens spécialisés en transplantation qui prennent des décisions relatives au don d'organes ont été invités à répondre à un sondage électronique entre le 22 juillet et le 4 octobre 2022. Participants: L'invitation à participer a été distribuée par courriel à 179 néphrologues, chirurgiens et urologues canadiens spécialisés en transplantation. Les participants ont été identifiés en communiquant avec chaque program de transplantation pour obtenir une liste des médecins recevant des offres d'organes. Mesures: Les répondants devaient indiquer s'ils accepteraient ou refuseraient un donneur donné, en supposant qu'un receveur approprié existait. Ils étaient également invités à citer les raisons justifiant le refus d'un donneur. Méthodologie: Les taux d'acceptation par scénario (acceptation totale divisée par le nombre total de répondants pour un scénario donné, et pour l'ensemble) et les raisons du refus ont été déterminés et présentés sous forme de pourcentage du nombre total de cas refusés. Résultats: En tout, 72 professionnels issus de 7 provinces avaient répondu à au moins une question du sondage. On a observé une grande variabilité du taux d'acceptation entre les différents centers; le plus conservateur avait refusé 60,9 % des donneurs présentés alors que le plus entreprenant n'avait refusé que de 28,1 % des cas (p < 0,001). Les donneurs d'âge avancé, ceux décédés d'un problème cardiaque et ceux qui souffraient d'insuffisance rénale aiguë, d'insuffisance rénale chronique et de comorbidités étaient plus susceptibles d'être refusés. Limites: Comme pour toute étude sous forme de sondage, celle-ci comporte un possible biais de participation. Cette étude examine les caractéristiques du donneur de manière isolée, mais demande aux répondants de supposer qu'un candidat approprié existe. Dans la réalité, chaque fois que la qualité d'un donneur est évaluée, elle doit être prise en compte dans le contexte du receveur visé. Conclusion: Dans cette étude présentant des cas théoriques de complexité croissante sur le plan médical de donneurs de reins décédés, une importante variabilité a été observée quant au refus des donneurs par les spécialistes de la transplantation canadiens. Les taux relativement élevés de refus et l'apparente hétérogénéité des décisions liées à l'acceptation justifient plus d'éducation auprès des spécialistes de la transplantation canadiens; notamment sur les avantages pour un candidat approprié de recevoir un organe, même si ce dernier provient d'un cas médicalement complexe, par rapport au fait de rester en dialyze sur la liste d'attente pour une transplantation.

Standardized amino acid digestibility and true metabolizable energy for several increased protein ethanol co-products produced using back-end fractionation systems.

Precision-fed rooster trials were conducted to evaluate standardized AA digestibility and TMEn of the increased protein ethanol co-products corn fermented protein (CFP), high protein-distillers dried grains with solubles (HP-DDGS), and reduced fiber high protein-DDGS (RFHP-DDGS) produced using post-fermentation back-end fractionation systems. The TMEn was determined using conventional adult Leghorn roosters, while cecectomized roosters were used to determine standardized AA digestibility. Three to 6 roosters were fasted per treatment for 26 h prior to crop intubation with 27 g of sample and excreta were collected for 48 h post-feeding. Statistical analyses were conducted using a one-way ANOVA for a completely randomized design. Eight samples of CFP were found to contain a mean of 56% CP (DM basis) compared with a mean of 32% for conventional DDGS. The mean TMEn of CFP (3,556 kcal/kg) was greater (P < 0.05) than conventional DDGS1 and 2 (2,767 kcal/kg DM); mean standardized AA digestibility for CFP was similar to conventional DDGS and ranged from 88 to 94%. The mean digestible Lys, Met+Cys, and Thr concentrations for conventional DDGS were 0.79, 1.12, and 0.94%, respectively, whereas those for CFP were 1.74, 2.06, and 1.88%, respectively (DM basis). Two samples of HP-DDGS contained a mean of 51% CP (DM basis), a mean TMEn of 3,325 kcal/kg DM, a mean standardized AA digestibility of 90%, and mean concentrations of digestible Lys, Met+Cys, and Thr, which were 1.53, 1.77, and 1.60%, respectively (DM basis). The mean CP content of 2 RFHP-DDGS was 48% and the mean TMEn was 3,711 kcal/kg DM, which was greater (P < 0.05) than conventional DDGS3 and 4 (2,920 kcal/kg DM). Mean standardized AA digestibility of RFHP-DDGS was 90% and mean digestible Lys, Met+Cys, and Thr concentrations increased from 0.82, 1.01, and 0.95% for conventional DDGS, respectively, to 1.00, 1.59, and 1.44% for RFHP-DDGS, respectively (DM basis). Results indicate these high protein corn ethanol co-products have increased nutritional value for poultry compared with conventional DDGS.

Research Note: Evaluation of a precision-fed rooster assay for determination of phytic acid disappearance in feedstuffs.

The objective of this study was to evaluate a precision-fed rooster assay that is suitable for determination of phytic acid (myo-inositol 1,2,3,4,5,6-hexakis; InsP6) disappearance in plant-based feed ingredients. A 48-h precision-fed rooster assay was used to measure InsP6 disappearance using conventional White Leghorn roosters. A minimum of 4 individually-caged roosters per treatment were fasted for 26 h prior to crop intubation with 15 to 30 g of sample, and excreta were quantitatively collected for 48 h. Soybean meal, soybean hulls, canola meal, conventional distillers dried grains with solubles (DDGS), palm kernel meal (PKM), and wheat bran were evaluated in Experiment 1, whereas wheat middlings (WM) and rice bran (RB) were evaluated without and with 1,000 and 1,800 U/kg phytase in Experiment 2. Data from Experiment 1 were subjected to a one-way ANOVA for a completely randomized design, while data from Experiment 2 were subjected to two-way ANOVA for a 2 × 3 factorial arrangement of treatments. In Experiment 1, InsP6 disappearance ranged from 3 to 95% among all ingredients. The InsP6 disappearance for conventional DDGS (95%) was the highest (P < 0.05), wheat bran and soybean hulls were intermediate (47-48%), PKM was low (24%), and soybean meal and canola meal were very low (3-5%). In Experiment 2, there was a significant ingredient × phytase interaction (P < 0.05). Phytase inclusion at both 1,000 and 1,800 U/kg resulted in a significant improvement (P < 0.05) in InsP6 disappearance for RB; however, only the addition of 1,800 U/kg resulted in an increase in InsP6 disappearance for WM. The addition of 1,800 U/kg phytase increased the InsP6 disappearance from 58 to 74% for WM and from 26 to 53% for RB. These results suggest the precision-fed rooster assay can be used to evaluate phytic acid disappearance in plant-based feed ingredients and the assay was able to detect a significant effect of 1,800 U/kg of exogenous phytase on phytic acid disappearance for WM and RB.

Depression, anxiety and PTSD symptoms before and during the COVID-19 pandemic in the UK.

BACKGROUND: The impact of the coronavirus disease 2019 (COVID-19) pandemic on mental health is still being unravelled. It is important to identify which individuals are at greatest risk of worsening symptoms. This study aimed to examine changes in depression, anxiety and post-traumatic stress disorder (PTSD) symptoms using prospective and retrospective symptom change assessments, and to find and examine the effect of key risk factors. METHOD: Online questionnaires were administered to 34 465 individuals (aged 16 years or above) in April/May 2020 in the UK, recruited from existing cohorts or via social media. Around one-third (n = 12 718) of included participants had prior diagnoses of depression or anxiety and had completed pre-pandemic mental health assessments (between September 2018 and February 2020), allowing prospective investigation of symptom change. RESULTS: Prospective symptom analyses showed small decreases in depression (PHQ-9: -0.43 points) and anxiety [generalised anxiety disorder scale - 7 items (GAD)-7: -0.33 points] and increases in PTSD (PCL-6: 0.22 points). Conversely, retrospective symptom analyses demonstrated significant large increases (PHQ-9: 2.40; GAD-7 = 1.97), with 55% reported worsening mental health since the beginning of the pandemic on a global change rating. Across both prospective and retrospective measures of symptom change, worsening depression, anxiety and PTSD symptoms were associated with prior mental health diagnoses, female gender, young age and unemployed/student status. CONCLUSIONS: We highlight the effect of prior mental health diagnoses on worsening mental health during the pandemic and confirm previously reported sociodemographic risk factors. Discrepancies between prospective and retrospective measures of changes in mental health may be related to recall bias-related underestimation of prior symptom severity.

Persistence of sugars used for intestinal permeability measures in an in vitro rumen environment.

Orally administered synthetic sugars are routinely used as markers of intestinal permeability in nonruminants and young calves, but not adult ruminants, likely because of uncertainty surrounding degradation of such sugar markers (e.g., d-mannitol, sucralose, lactulose) in the rumen. The objective was to evaluate persistence of d-mannitol, sucralose, and lactulose in a closed in vitro rumen fermentation system over 48 h. The null hypothesis was that sugar concentration would not be affected by time. Rumen contents were collected and processed under anerobic conditions a total of 12 times from a ruminally cannulated lactating Holstein cow. These 12 rumen samplings reflect 4 in vitro experiments (d-mannitol, sucralose, lactulose, and d-glucose as a positive methodological control), each replicated 3 times. For each replication, filtered rumen contents and rumen buffer (1:3; vol/vol) were added to a series of six 500-mL flasks, each containing 3 filter bags. Each filter bag contained 500 mg of ground total mixed ration (94.2% dry matter; 15.2% crude protein, 40.9% neutral detergent fiber, 3.9% fat, and 6.2% ash, dry matter basis) and three 5-mm glass beads. The 6 flasks represented 0, 6, 12, 24, and 48 h time points, and a 48-h negative control flask. A single sugar was tested during each experimental replicate. Final flask concentrations of each sugar were 4.07 mg/mL d-glucose, 1.99 mg/mL d-mannitol, 2.17 mg/mL sucralose, or 3.10 mg/mL lactulose. Flasks were incubated under anerobic conditions at 39°C where they remained undisturbed until the designated time of removal (0, 6, 12, 24, or 48 h). At removal, an aliquot of each flask was removed and sugar concentration was quantified by HPLC-mass spectrometry. Data for each experiment were analyzed using an ANOVA model that included the single fixed effect of time (0, 6, 12, 24, or 48 h); flask within replicate was the random term. Lactulose was not resolved in any samples due to interfering components within the sample matrix; no lactulose data are presented. As expected, positive methodological control of glucose decreased to negligible concentrations by 6 h of in vitro incubation. d-Mannitol followed the same pattern as glucose, which was different from our hypothesis. The interpretation is that d-mannitol is degraded in the in vitro rumen culture system and, by extension, is therefore not a viable choice to use in in vivo intestinal permeability tests in adult ruminants when dosed orally. As hypothesized, sucralose concentration did not change over 48 h of incubation in a closed in vitro rumen fermentation system. This suggests feasibility of orally dosed sucralose in adult ruminants as a rumen-inert marker of intestinal permeability with subsequent analysis of biological samples (e.g., urine, blood) by HPLC-mass spectrometry.

Metabolizable energy and amino acid digestibility in spray-dried animal plasma using broiler chick and precision-fed rooster assays.

Four experiments were conducted to determine ME and amino acid (AA) digestibility of spray-dried animal plasma (SDAP) and soybean meal (SBM). The 48-h precision-fed adult rooster assay was used in 2 experiments; TMEn and standardized AA digestibility were determined using conventional and cecectomized roosters, respectively, 50 weeks of age and weighing approximately 2,200 g. Eight individually-caged roosters (4 per diet) were fasted for 26 h, then precision-fed 30 g of SDAP mixture (containing 50% corn) or SBM mixture (containing 50% corn). The TMEn and AA digestibility for SDAP and SBM were calculated by the difference procedure. The TMEn for SDAP was greater (P < 0.05) than SBM (3,743 and 2,669 kcal/kg DM, respectively). Similarly, mean AA digestibility of SDAP was greater (P < 0.05) than SBM (94 and 86%, respectively). Two assays were conducted using Ross male broilers to determine AMEn and apparent (AIAAD) and standardized (SIAAD) ileal AA digestibility of SDAP and SBM. A 3 × 2 factorial arrangement of treatments was used to determine AMEn; 126 chicks (6 replicate pens of 7 chicks) were fed a corn-SBM-based reference diet, a diet containing 30% SDAP, or a diet containing 30% SBM from d 7 to 10 and 18 to 21. A 2 × 2 factorial arrangement of treatments was used to determine AIAAD and SIAAD; 168 chicks (12 replicate pens of 7 chicks) were fed a semi-purified diet containing 25% SDAP or a semi-purified, isonitrogenous diet containing 41% SBM from d 7 to 10 and 18 to 21. The AMEn for SDAP was greater (P < 0.05) than SBM at d 10 (3,851 and 2,089 kcal/kg DM, respectively) and d 21 (4,239 and 2,849 kcal/kg DM, respectively). The second assay showed an increase (P < 0.05) in AIAAD and SIAAD for SDAP compared with SBM at d 10 (mean SIAAD for SDAP and SBM were 96% and 84%, respectively) and d 21 (97% and 87%, respectively). Regardless of assay or age, these results indicate SDAP is a highly digestible feed ingredient with high ME and AA digestibility.

Assessment of Activity Profiles in Older Adults and Lower Limb Bone Parameters: Observations from the Hertfordshire Cohort Study.

As muscle strength and function decline with age the optimal high-impact physical activity (PA) required for bone remodelling is rarely achievable in older adults. This study aimed to explore the activity profiles of community-dwelling older men and women and to assess the relationship between individual PA profiles and lower limb bone parameters. Participants from the Hertfordshire Cohort Study wore triaxial accelerometers for 7 days and counts of low (0.5-1.0 g), medium (1.0-1.5 g), and high (> 1.5 g) vertical-impact activity were calculated. Two years later, participants underwent a pQCT scan of the tibia (4% and 38% sites) to obtain measures of bone mineral density and bone geometry. Linear regression was used to quantify associations between bone and PA loading profiles adjusting for age, sex, loading category, and BMI. Results are presented as ß [95% confidence interval]. Bone and PA data were available for 82 participants. The mean (SD) age at follow-up was 81.4(2.7) years, 41.5% (n = 34) were women. The median low-impact PA count was 5281 (Inter-quartile range (IQR) 2516-12,977), compared with a median of only 189 (IQR 54-593) in medium, and 39 (IQR 9-105) in high-impact counts. Positive associations between high-impact PA and cortical area (mm2), polar SSI (mm3), and total area (mm2) at the 38% slice (6.21 [0.88, 11.54]; 61.94 [25.73, 98.14]; 10.09 [3.18, 16.99], respectively). No significant associations were found at distal tibia. These data suggest that maintaining high (> 1.5 g)-impact activity is difficult for older adults to achieve; however, even small amounts of high-impact PA are positively associated with selected cortical bone parameters 2 years later.

Evaluation of the precision-fed rooster assay for detecting effects of supplemental enzymes on metabolizable energy.

The precision-fed rooster assay has been used extensively to determine nitrogen-corrected true metabolizable energy (TMEn) of feed ingredients for poultry. However, this assay has not generally been used to evaluate effects of supplemental enzymes for this purpose. Therefore, 2 precision-fed rooster assays were conducted to evaluate several different carbohydrase enzymes on TMEn for a corn/soybean meal diet, a pearled barley diet, and diets containing different inclusion levels of rye/corn. In both rooster assays, Single Comb White Leghorn roosters were fasted for 26 h and then crop intubated with either 25 or 30 g of the test diets, depending on the assay. Excreta were then collected quantitatively for 48 h after feeding. In the first rooster assay with 56 birds, 6 carbohydrase combinations and/or levels (xylanase/alpha-galactosidase were evaluated using a corn/soybean meal control diet. All carbohydrase additions either numerically or significantly (P < 0.05) increased TMEn and the mean increase for the enzyme treatments was 66 kcal/kg DM compared with the corn/soybean meal control diet. The second assay consisted of twenty dietary treatments; 120 roosters were crop-intubated with 25 g of diets that were composed of 100% barley, 100% rye, 50% rye: 50% corn, or 25% rye: 75% corn. The diets were fed with and without inclusion of 2 different levels of either ß-glucanase, xylanase, or a multi-carbohydrase combination. Both ß-glucanase and the multi-carbohydrase significantly (P < 0.05) increased TMEn of the 100% barley diet, with the multi-carbohydrase increasing it from 3,722 to 4,086 kcal/kg DM at the highest inclusion rate. The xylanase and multi-carbohydrase either numerically or significantly (P < 0.05) increased TMEn of the 100% rye diet, with the multi-carbohydrase increasing it from 3,581 to 3,909 kcal/kg DM at the highest inclusion rate. The magnitude of enzyme response decreased as the level of rye in the diets decreased. Overall, results of this study indicated that the precision-fed rooster assay can detect effects of enzymes, primarily carbohydase, on TMEn of diets containing corn/soybean meal, pearled barley, and/or rye.

A survey study investigating perceptions and acceptance of the whole-body imaging techniques used for the diagnosis of myeloma.

INTRODUCTION: The purpose of this study was to investigate patient perceptions and acceptance of the three whole-body imaging (WBI) modalities used for diagnosing myeloma; radiographic skeletal survey (RSS), low-dose whole-body computed tomography (LD-WBCT) and whole-body magnetic resonance imaging (WB-MRI). The secondary aim was to explore the factors affecting the acceptance of whole-body imaging for myeloma. METHODS: 60 participants (median age = 58.5 years old) recruited from three NHS trusts and social media completed a survey in which they scored their experiences of each WBI modality on nine 5-point rating scales. Spearman's correlation coefficient, Kruskal-Wallis, Mann-Whitney and Wilcoxon signed-rank tests were used to compare scores between different WBI techniques. Participants were invited to provide additional open text responses for interpretation using thematic analysis. RESULTS: All modalities demonstrated high levels of acceptability (median score = 4). WB-MRI was perceived as more stressful (p=<0.01) and claustrophobic (p=<0.01) than RSS and LD-WBCT. Thematic analysis showed patients understood the importance of imaging but had concerns about exacerbated pain and the results. WB-MRI was difficult to tolerate due to its duration. Respondents were averse to the physical manipulation required for RSS while remaining stationary was perceived as a benefit of LD-WBCT and WB-MRI. Staff interactions had both positive and negative effects on acceptance. CONCLUSIONS: Despite the psychological and physical burdens of WBI, patients accepted its role in facilitating diagnosis. Staff support is vital for facilitating a positive whole-body imaging experience. Healthcare practitioners can improve WBI acceptance by understanding the burdens imposed by WBI and adopting the personalised care model. IMPLICATIONS FOR PRACTICE: Patient experience can be improved by tailoring examinations to individual needs. RSS can be as burdensome as other WBI techniques and could be superseded by LD-WBCT or WB-MRI.

Phosphorus digestibility and relative phosphorus bioavailability in two dried black soldier fly larvae meals and a defatted black soldier fly larvae meal in broiler chickens.

Two chicken assays were conducted to determine P availability, using three different approaches, for 2 black soldier fly larvae meals (BSFL 1 and 3) and one partially-defatted BSFL. Experiment 1 was conducted to determine ileal P digestibility and total tract P retention. Three experimental diets containing a BSFL as the only source of P were fed to broiler chickens from 19 to 22 days of age. Each diet contained 0.25% total dietary P. Ileal digesta and excreta were collected on day 22. Ileal digestibility of P was 87%, 75%, and 88% for BSFL 1, BSFL 3, and partially-defatted BSFL, respectively. Total tract P retention was 87%, 73%, and 85% for BSFL 1, BSFL 3, and partially-defatted BSFL, respectively. The objective of experiment 2 was to determine the relative bioavailability of P in the 3 insect meals relative to KH2PO4 using a chicken bone ash bioassay. Chickens were fed one of nine dietary treatments from 8 to 22 days of age. These diets included a P-deficient cornstarch-dextrose-SBM based diet (0.14% nonphytate P) or that diet supplemented with 0.05% or 0.10% P from KH2PO4, 7% or 14% BSFL 1, 8%, or 16% BSFL 3, and 8% or 16% partially-defatted BSFL. The slope-ratio method using multiple regression for tibia ash regressed on supplemental P intake was used to calculate the relative bioavailability of P where values for BSFL 1, BSFL 3, and partially-defatted BSFL were 54%, 51%, and 57%, respectively, relative to KH2PO4. The results of this study indicated that availability of P in BSFL based on ileal P digestibility and total tract P retention values was high, whereas relative bioavailability values for P based on tibia ash were approximately 20 to 30 percentage units lower.

True metabolizable energy and amino acid digestibility in black soldier fly larvae meals, cricket meal, and mealworms using a precision-fed rooster assay.

Six precision-fed rooster assays were conducted to determine nutrient composition, nitrogen-corrected true metabolizable energy (TMEn) and standardized amino acid digestibility for three black soldier fly larvae meals (BSFL), one partially-defatted BSFL, one cricket meal and two mealworm meals. The TMEn values were determined in three 48-h rooster assays using conventional roosters and the standardized amino acid digestibility values were determined in three 48-h rooster assays using cecectomized roosters. Nutrient analysis (DM basis) of the meals indicated that the CP varied from 45 to 58% among the four BSFL, was 67% for the cricket meal and varied from 51 to 56% for the two mealworms. Crude fat (12-30%), total P (0.7-1.1%), Ca (0.04-3.6%), and neutral detergent fiber (10-36%) also varied among the insect meals. The TMEn values for the three BSFL were generally consistent and averaged 4079 kcal/kg DM. As expected, partially-defatted BSFL contained a lower level of TMEn. The TMEn of the cricket meal was 4223 kcal/kg DM. Due to their low fiber content and high fat content, the TMEn values for the two mealworms were high and in excess of 5000 kcal/kg DM. Amino acid concentrations of the various insect meals ranged from 0.69 to 1.1% for methionine, 0.57 to 0.73% for cystine, 3.3 to 4.5% for lysine, and 1.9 to 2.6% for threonine. Standardized amino acid digestibility values were generally high (most were 85-95%) for the four BSFL and two mealworms. Digestibility values for most amino acids were slightly lower for the cricket meal. Digestibility of cystine and valine were generally lower and more variable than other amino acids in the seven insect meals. The results of this study indicated that nutrient composition varies substantially among different insect meals, but all insect meals contained high levels of TMEn and digestible amino acids compared with feed ingredients commonly used in poultry diets.