[Periodic dynamic observation and analysis of cellular and humoral immunity indexes of adults infected with Omicron BA.1].

Objective: To analyze the immunological characteristics and antibody changes of patients infected with the Omicron BA.1 and evaluate the possibility of secondary infection. Methods: A total of 104 patients infected with Omicron BA.1 in the Jinnan District of Tianjin from January 8 to February 2, 2022, were included in the study. The control group and case group were matched 1∶1 based on age, sex and vaccination status. Serum was collected from the case group and control group at 3, 6 and 9 months after infection. The serum levels of interleukin4 (IL-4), IL-5 and interferon-gamma (IFN-γ), as well as the positive rates of IgG, IgG1 and IgG2, were detected by ELISA. Results: The highest concentration of IFN-γ in the case group at 6 months after infection was 145.4 pg/ml, followed by a decrease in concentration. The concentrations of IL-4 and IL-5 began to decrease at 6 months after infection (all P<0.001). There was no significant difference in the IgG2 positive rate between the case group and the control group at 6 months after BA.1 infection. However, at 9 months, there was a significant decrease compared to the control group (P=0.003). The ratio of IFN-γ/IL4 at 3 months after infection in the case group was lower than that in the control group (P<0.001). There was no significant difference in the ratio between the case group and the control group at 9 months after infection. Conclusion: The cellular immune function has been impaired at 3 months after infection with BA.1, and the specific cellular immune and humoral immune functions decrease significantly after 6 months, and the risk of secondary infection increases.

Modulation of rumen fermentation and microbial community through increasing dietary cation-anion difference in Chinese Holstein dairy cows under heat stress conditions.

AIMS: The effect of increasing dietary cation-anion difference (DCAD) on rumen fermentation and ruminal microbial community in dairy cows under heat stress (HS) conditions were evaluated. METHODS AND RESULTS: This study was performed as a two-period cross-over design during the summer season, with eight lactating dairy cows randomly distributed to either a control DCAD diet (CON: 33·5 mEq/100 g DM) or high DCAD diet (HDCAD: 50·8 mEq/100 g DM). Throughout the present study, the temperature and humidity index (THI; 80·2 ± 4·29) was generally elevated above the threshold (THI = 72) that is reported to cause HS in lactating dairy cows. Rumen liquid samples were collected on 15 and 21 d during each 21 d-period. The absolute concentration of ruminal total volatile fatty acid (TVFA) in HDCAD treatment was significantly (P < 0·05) higher than those in the control, whilst the ruminal pH, NH3 -N, and VFA molar percentages were unaffected through increasing DCAD. Furthermore, the copy numbers of the cellulolytic bacteria Ruminococcus albus and Ruminococcus flavefaciens in rumen fluid significantly (P < 0·05) rose along with the increment of DCAD. Although the Alpha diversity indexes and the bacterial microbiota structure were unaffected, increasing DCAD significantly (P < 0·05) enriched the phylum Fibrobacteres and genus Fibrobacter in the microflora of rumen fluid, whilst the genera Flexilinea and Dubosiella were the most differentially abundant taxa in the control. CONCLUSIONS: Increasing DCAD under HS conditions resulted in a greater concentration of total VFA without affecting rumen bacteria diversity or structure, although the enrichment of some cellulolytic/hemicellulolytic bacteria was observed. SIGNIFICANCE AND IMPACT OF THE STUDY: The present study provides information on the modulation of rumen fermentation and microbial community through the increment of DCAD in Holstein dairy cows under HS conditions.

Saccharomyces cerevisiae as a probiotic feed additive to non and pseudo-ruminant feeding: a review.

The production of livestock and poultry faces major challenges to meet the global demand for meat and dairy products and eggs due to a steady increase in the world's population and the ban of antibiotics in animal production. This ban has forced animal nutritionists to seek for natural alternatives to antibiotics. In this context, the yeast Saccharomyces cerevisiae has received considerable attention in the last decade. It has been reported that feed supplementation with live yeast cells improve feed efficiency, enhance feed digestibility, increase animal performance, reduce the number of pathogenic bacteria, improve animal health and reduce the negative environmental impacts of livestock production. The current review sheds light on the effects of the use of live S. cerevisiae cells in the diets of nonruminant and pseudo-ruminant's animals and the mechanisms by which they exert its effects. This review work revealed that the addition of S. cerevisiae in poultry feed causes a phenomenon called competitive exclusion of pathogenic bacteria capable of causing disease adhere to the yeast surface, and so removing a large amount of harmful micro-organisms and allowing the Animal defend more effectively, the production of antimicrobial agents, the balancing the gut microbiota and stimulation of host adaptive immune system and improving gut morphological structure, thus these benefits are reflected on the overall poultry health. In addition, in the presence of live S. cerevisiae cells, the immunity of rabbits was improved due to the high number of white blood cell. In addition, apparent digestibility of acid and neutral detergent fibre was improved in horses and rabbits. Saccharomyces cerevisiae in pig diets augment mucosal immunity by increasing IgM and IgA activity against pathogens, enhance intestinal development and function, adsorb mycotoxins, modulate gut microbiota and reduce postweaning diarrhoea.

Isoindoline nitroxide-labeled porphyrins as potential fluorescence-suppressed spin probes.

A series of isoindoline nitroxide-labeled porphyrins were synthesized by the reaction of 5-phenyldipyrromethane and 5-(4'-carboethoxy-methyleneoxyphenyl)dipyrromethane with 5-formyl-1,1,3,3-tetramethylisoindolin-2-yloxyl (FTMIO) using the Lindsey method. The corresponding water-soluble spin-labeled porphyrins were also prepared. Subsequently, these compounds were characterized and their in vitro properties were evaluated. The electrochemical assay demonstrated that these isoindoline nitroxide-labeled porphyrins had similar electrochemical and redox properties to 5-carboxy-1,1,3,3-tetramethylisoindolin-2-yloxyl (CTMIO). The electron paramagnetic resonance test showed that these porphyrins exhibited hyperfine splittings and characteristic spectra of CTMIO with typical nitroxide g-values and nitrogen isotropic hyperfine coupling constants. The in vitro cytotoxicity assay indicated that these porphyrins possessed low cytotoxicity to human renal tubular epithelial 293T cells (normal cells) and human hepatoma HepG2 cells (tumor cells). Fluorescence spectroscopy revealed that free base isoindoline nitroxide-labeled porphyrins exhibited fluorescence suppression characteristic of nitroxide-fluorophore systems. In vitro fluorescene imaging demonstrated that the reduced isoindoline nitroxide-labeled porphyrins eliminated fluorescence suppression and displayed strong red fluorescence imaging in HepG2 cells. Thus these isoindoline nitroxide-labeled porphyrins may be considered potentially as biological spin probes for fluorescence imaging and EPR spectroscopy.

Effect of tea catechins on regulation of cell proliferation and antioxidant enzyme expression in H2 O2 -induced primary hepatocytes of goat in vitro.

Tea catechins (TC) are polyphenols that have potent antioxidant activity. The objectives of this study were to determine the effects of TC on antioxidant status of hepatocytes challenged with H2 O2 . Primary hepatocytes of goat were exposed to 1 mm H2 O2 without or with 5, 50 and 500 µg/ml TC. The cells were harvested at 48 h post-treatment to determine effects of TC on proliferation, apoptotic features and membrane integrity of cells, and expression of genes and activities of antioxidant enzymes. H2 O2 exposure caused damage to cells (p < 0.001). A lower concentration of TC (5 µg/ml) displayed a protective effect by inhibiting exorbitant cell proliferation and DNA degradation. Both H2 O2 exposure and TC pre-incubation affected expression of antioxidant enzymes at mRNA and protein levels (p < 0.001). The activities of catalase (CAT) (p = 0.027), CuZn-superoxide dismutase (CuZn-SOD) (p < 0.001) and glutathione peroxidase (GPx) (p < 0.001) increased with TC pre-incubation followed by H2 O2 challenge. Changes of CuZn-SOD activity induced by H2 O2 and TC basically paralleled the changes in the corresponding mRNA and protein levels, but the correlation in CAT and GPx expression displayed slightly different patterns at different concentrations of TC. These findings infer that oxidative stress can induce deleterious cellular responses and this unfavourable condition may be alleviated by treatment with TC.

Chemical composition and nutritive value of four varieties of cassava leaves grown in South-Western Nigeria.

The nutritive value of leaves of four varieties of cassava - MS 6, TMS 30555, Idileruwa and TMS 30572 was evaluated based on their chemical composition and in vitro fermentation. Crude protein (CP) contents of cassava leaves ranged from 177 to 240 g/kg dry matter (DM), with TMS 30555 showing the highest CP contents. Neutral detergent fibre (NDFom) and acid detergent fibre (ADFom) contents of cassava leaves ranged from 596 to 662 and 418 to 546 g/kg DM respectively. Condensed tannin (CT) and hydrocyanic acid contents ranged from 1.0 to 3.8 g/kg and 58.5 to 86.7 mg/kg DM respectively. The range of volatile fatty acids (VFA) in the supernatant after in vitro incubation of the cassava varieties was: acetate (14.7-31.5 mmol/l); propionate (4.5-6.3 mmol/l); butyrate (3.1-3.9 mmol/l); valerate (0.4-0.6 mmol/l); iso-butyrate (0.6-1.3 mmol/l); iso-valerate (1.1-1.9 mmol/l). The acetate:propionate ratio resulting from fermentation of TMS 30555 was higher(p < 0.05) than that of the other leaves. The highest in vitro gas production of 50.5 ml/200 mg DM was recorded for MS6 being higher (p < 0.05) than for TMS 30572, but similar to TMS 30555 and Idileruwa. The DM, CP, ADF and HCN contents of cassava leaves were positively correlated with gas production, while CT content was negatively correlated with gas production. The study showed that leaves of the varieties MS 6 and TMS 30555 are superior to the others in terms of CP and gas production indicating a higher digestibility and energy content and thus nutritive potential. They may therefore serve as supplements for ruminants fed on poor roughages.

Milk powder induced lipid peroxidation reduction using Ku Ding tea (Lactuca taiwaniana Maxim) in rats.

The effects of Ku Ding tea (Lactuca taiwaniana Maxim) and milk powder on biochemical and immunological parameters of Sprague-Dawley rats were investigated and the possibility of use of Ku Ding tea to reduce physiological discomfort of drinking milk powder was assessed. Eighty rats were randomly assigned to four treatments: basal diet (control), basal diet plus whole milk powder (WM), basal diet plus Ku Ding tea (KD) and basal diet plus whole milk powder and Ku Ding tea (MK). Data was collected on animals' final body weight, hematological values, blood biochemical parameters, antioxidation parameters and immune organ weight index. Results showed that final body weight of male KD was significantly lower than that of WM. White blood cell count, monocyte count and granulocyte count of KD rats were significantly lower than those of WM. Compared to the control, single milk powder supplementation numerically increased plasma malondialdehyde. The malondialdehyde in the male KD and MK rats were lower than those in WM and control, although the differences were not significant. No significant differences were found in Na(+)K(+)-adenosine triphosphatase activity, spleen and thymus index in each group. Consumption of Ku Ding tea appeared to lower lipid peroxidation that was induced by milk powder in the rats.

The protective effect of high heme oxygenase-1 expression induced by propofol on the alveolar II type epithelial cells of rats with acute lung injury induced by oleic acid.

This study aimed to investigate the mechanism of propofol (PR) pretreatment inducing high heme oxygenase-1 (HO-1) expression to protect alveolar type II epithelial cells (AEC-II) in rats with acute lung injury (ALI) induced by oleic acid (OA). In this study, 32 male Sprague-Dawley rats (250 - 300 g) were randomly divided into four groups (n = 8 in each group) as follows: group C (the normal control group), the OA group (the oleic acid injury control group), the OA + PR group (the PR pretreatment group), and the OA + IX group (the zinc porphyrin IX pretreatment group). Arterial blood gases, bronchoalveolar lavage fluid (BALF), and serum pulmonary surfactant-associated protein A (SP-A) were measured in each group. The changes in the AEC-II ultrastructure were observed under an electron microscope. The HO-1 protein expression was detected by immunohistochemistry, and HO-1 messenger ribonucleic acid (mRNA) was detected by polymerase chain reaction. The results of this study showed that there were significant differences in PO2, pCO2, and PaO2/FiO2 among the different groups (p < 0.05). The difference between BALF and SP-A in each group was statistically significant (p < 0.01). There were also significant differences in the integrated optical density of the HO-1 protein expression and HO-1 mRNA in the pulmonary tissue of the different groups (p < 0.05 or p < 0.01). The results of the electron microscopy showed that AEC-II were relatively irregular in the OA group. The cells degenerated and even disintegrated, the microvilli on the cell surface decreased, the lamellar bodies in the cytoplasm were evacuated, and some were discharged into the alveolar cavity. The above-mentioned changes in the OA + PR group were lower than in the OA group, while the changes were greater in the OA + IX group, compared with those in the OA group. We conclude that PR can significantly increase the expression of HO-1 in pulmonary tissues and reduce pulmonary injury, and, therefore, protect the AEC-II.

The effect of dietary methionine levels on endogenous nitrogen and endogenous amino acids flows in growing goats.

The effect of dietary methionine (Met) levels on endogenous N and amino acids (AA) flows at different part of the digestive tract of growing goats was determined using a (15)N isotope dilution technique. Three goats (25 ± 2.5 kg) were fitted with the ruminal, duodenal and ileal cannulae and allocated to three dietary treatments in a 3 × 3 Latin square design. The dietary treatments consisted of a total mixed ration containing three levels of Met (0.15%, 0.25% and 0.35%) respectively. It was found that at 0.15% Met level, the lowest flow in endogenous N and total AA at the duodenum and ileum occurred. The endogenous N secretion contributed to 26% and 23% of the duodenal and ileal total N flows, respectively, and the proportions were not affected by the dietary Met levels. The duodenal and ileal flows of endogenous total AA were 11.1, 11.8, 11.3 g/d and 2.9, 3.9, 4.1 g/d respectively. The average real digestibility of N was 65%, 87% and 95% in the forestomach, intestine and whole digestive tract respectively.

Effects of variety, sowing season and maturity stage on ruminal phosphorus release from whole maize stover and its morphological fractions.

An in situ degradation technique was used to investigate the effects of variety, season and maturity stage on ruminal Phosphorus (P) release from whole maize stover and morphological fractions from five varieties of maize (conventional maize, CM; sweet maize, SM; waxy maize, WM; high oil maize, HOM; and fodder maize, FM). Maize plants were harvested in 2005, 17 and 31 days after tasselling and manually separated into leaf blade, leaf sheath, stem and husk. Results showed that the values of rapidly released P fractions (a), slowly released P fractions (b), rate constant of P release for fraction b (c) and effective disappearance (ED) of P were significantly influenced by variety, sowing season and maturity stage (p < 0.05). The ED of P in whole maize stover among the varieties decreased in the following order: FM (89.8%) > HOM (87.9%) > CM (87.0%) > SM (86.9%) > WM (83.9%). Advanced maturity stage increased (p < 0.001) the a and ED values of P in the leaf blade and leaf sheath, but decreased (p < 0.001) these parameters in the husk. The a fraction and ED of P were higher (p < 0.001) for maize sown in spring than those sown in summer. Significant (p < 0.05) interactions among variety, sowing season and maturity stage were noted in the a and ED values of P. Effective disappearance of morphological fraction varied significantly (p < 0.001) and followed the order: stem (90.3%) > leaf sheath (88.2%) > leaf blade (85.2%) > husk (84.9%). In conclusion, most of P in maize stover could be released in the rumen. The potential pollution resulting from P excretion in faeces may be alleviated, when maize stover is largely used as the main forage source of ruminants.

[Genotyping on one case with Chikungunya infection introduced into Tianjin in China from Myanmar].

Objectives: A clinical case caused by Chikungunya virus (CHIKV) was introduced into Tianjin, China from Myanmar. The current study is aimed to phylogenetically analyzing this imported strain and to reveal the relationship between this virus and other circulating CHIKV strains. Methods: RNA was extracted from serum of the suspected patient presenting with symptoms compatible with CHIKV infections. Real-time reverse transcription PCR (RT-PCR) assay was used for diagnoses of the patient. For phylogenetic analysis, envelope glycoprotein 1 (E1) gene of CHIKV was amplified by two-step RT-PCR and the products were sequenced. Results: The phylogenetic analyses revealed that the imported CHIKV belong to Indian Ocean Lineage (IOL) derived from ECSA genotype and sharing the same cluster with the Aede albopitus-adapted strains that triggered the outbreaks in Pakistan (2016), Italy (2017) and Bangladesh (2017). Conclusion: The imported CHIKV strain has the potential to cause explosive outbreaks in China and this event happened in Tianjin calls for strengthening the monitoring programs on mosquito-borne diseases in China.

Quantitative evaluation of ruminal methane and carbon dioxide formation from formate through C-13 stable isotope analysis in a batch culture system.

Methane produced from formate is one of the important methanogensis pathways in the rumen. However, quantitative information of CH4 production from formate has been rarely reported. The aim of this study was to characterize the conversion rate (CR) of formic acid into CH4 and CO2 by rumen microorganisms. Ground lucerne hay was incubated with buffered ruminal fluid for 6, 12, 24 and 48 h. Before the incubation, 13C-labeled H13COOH was also supplied into the incubation bottle at a dose of 0, 1.5, 2.2 or 2.9 mg/g of DM substrate. There were no interactions (P>0.05) between dose and incubation time for all variables evaluated. When expressed as an absolute amount (ml in gas sample) or a relative CR (%), both 13CH4 and 13CO2 production quadratically increased (P<0.01) with the addition of H13COOH. The total 13C (13CH4 and 13CO2) CR was also quadratically increased (P<0.01) when H13COOH was added. Moreover, formate addition linearly decreased (P<0.031) the concentrations of NH3-N, total and individual volatile fatty acids (acetate, propionate and butyrate), and quadratically decreased (P<0.014) the populations of protozoa, total methanogens, Methanosphaera stadtmanae, Methanobrevibacter ruminantium M1, Methanobrevibacter smithii and Methanosarcina barkeri. In summary, formate affects ruminal fermentation and methanogenesis, as well as the rumen microbiome, in particular microorganisms which are directly or indirectly involved in ruminal methanogenesis. This study provides quantitative verification for the rapid dissimilation of formate into CH4 and CO2 by rumen microorganisms.

Dietary starch and rhubarb supplement increase ruminal dissolved hydrogen without altering rumen fermentation and methane emissions in goats.

Hydrogen is an important intermediate that is produced during carbohydrate fermentation to volatile fatty acid and utilized by methanogens to produce methane in the rumen. Ruminal volatile fatty acid and dissolved methane concentrations are more than 500 times greater than dissolved hydrogen concentration. Therefore, we hypothesized that dissolved hydrogen might have a higher sensitivity in response to dietary changes compared with volatile fatty acid and dissolved methane. Using goats, we investigated the effects of increasing dietary starch content (maize replaced with wheat bran) and supplementing with rhubarb rhizomes and roots on the relationships among dissolved hydrogen, dissolved methane and other fermentation end products. The study was conducted in a replicated 4×4 Latin square with a 2×2 factorial arrangement of four treatments: two starch levels (220 v. 320 g/kg dry matter (DM)), without and with rhubarb supplement (0% v. 2.8% of total mixed ration). Increased dietary starch and rhubarb supplementation did not alter volatile fatty acid concentrations or methane emissions in terms of g/day, g/g DM intake and g/g organic matter digested. However, goats fed the high-starch diet had greater dissolved hydrogen (P=0.005) and relative abundance of Selenomonas ruminantium (P<0.01), and lower (P=0.02) copy number of protozoa than those fed the low-starch diet. Rhubarb increased ruminal dissolved H2 (P=0.03) and total volatile fatty acid concentration (P<0.001), but decreased copies of bacteria (P=0.002). In conclusion, dissolved hydrogen appears to be more sensitive to dietary changes with starch content and rhubarb supplementation, when compared with volatile fatty acid concentrations and methane production.

Postnatal differential expression of chemoreceptors of free fatty acids along the gastrointestinal tract of supplemental feeding v. grazing kid goats.

The gastrointestinal tract (GIT) of animals is capable of sensing various kinds of nutrients via G-protein coupled receptor-mediated signaling transduction pathways, and the process is known as 'gut nutrient chemosensing'. GPR40, GPR41, GPR43 and GPR119 are chemoreceptors for free fatty acids (FFAs) and lipid derivatives, but they are not well studied in small ruminants. The objective of this study is to determine the expression of GPR40, GPR41, GPR43 and GPR119 along the GIT of kid goats under supplemental feeding (S) v. grazing (G) during early development. In total, 44 kid goats (initial weight 1.35±0.12 kg) were slaughtered for sampling (rumen, abomasum, duodenum, jejunum, ileum, cecum, colon and rectum) between days 0 and 70. The expression of GPR41 and GPR43 were measured at both mRNA and protein levels, whereas GPR40 and GPR119 were assayed at protein level only. The effects of age and feeding system on their expression were variable depending upon GIT segments, chemoreceptors and expression level (mRNA or protein), and sometimes feeding system × age interactions (P0.05) on GPR43 expression; and there were no feeding system×age interactions (P>0.05) on GPR41 and GPR43 protein expression. The expression of GPR41 and GPR43 in rumen and abomasum linearly (P<0.01) increased with increasing age (from days 0 to 70). Meanwhile, age was the main factor affecting GPR40 expression throughout the GIT. These outcomes indicate that age and feeding system are the two factors affecting chemoreceptors for FFAs and lipid derivatives expression in the GIT of kids goats, and S enhanced the expression of chemoreceptors for FFAs, whereas G gave rise to greater expression of chemoreceptors for lipid derivatives. Our results suggest that enhanced expression of chemoreceptors for FFAs might be one of the benefits of early supplemental feeding offered to young ruminants during early development.

Effects of substitution of different levels of steam-flaked corn for finely ground corn on lactation and digestion in early lactation dairy cows.

Eight multiparous Holstein cows, 4 of them fitted with rumen cannulas, were used to test the effects of substitution of steam-flaked corn (SFC) for equal amounts of finely ground corn (FGC) in diets on feed intake and digestion, blood metabolites, and lactation performance in early lactation dairy cows. Cows were fed 4 diets in a replicated 4 x 4 Latin square design. The fistulated cows formed 1 replicate. Each experimental period lasted for 3 wk. The 4 diets contained 0, 10, 20, or 40% SFC and 40, 30, 20, or 0% FGC (dry matter basis), respectively. The milk protein content and yield, milk solid nonfat content and yield, plasma glucose concentration, and dry matter intake increased as the proportion of SFC increased in diets. Apparent total tract digestibilities of dry matter, organic matter, neutral detergent fiber, acid detergent fiber, and average ruminal fluid NH(3)-N concentration decreased with increasing levels of SFC. The ruminal fluid pH was not affected by the substitution of SFC for FGC. The 20% SFC substitution improved digestion of crude protein, yield of fat-corrected milk, milk lactose content, fat, and fat yield. The 40% SFC substitution increased urea concentration in both plasma and milk. It was concluded that 20% of SFC substitution for FGC appeared to be an appropriate level in diet for early lactation dairy cows.

Effects of vitamin A supplementation on growth performance, carcass characteristics and meat quality in Limosin×Luxi crossbreed steers fed a wheat straw-based diet.

Three experiments were conducted to examine the effects of dietary vitamin A supplementation on performance and carcass parameters in Limosin×Luxi crossbreed finishing steers fed a wheat straw-based diet. Sixteen 12-month old (301±22kg) steers, 16 12-month old (309±15kg) steers and 16 24-month old (411±20kg) steers were used in experiment 1 for 6 months feeding period, in experiment 2 for three months feeding period and in experiment 3 for three months feeding period, respectively. Sixteen steers of each experiment were randomly divided into the four groups of four animals. Treatments consisted of four vitamin A supplementation levels (0, 1100, 2200 and 4400IU/kg DM). The growth rate was affected by dietary vitamin A level in experiment 1 and 2, revealing that the suitable amount of vitamin A supplementation increased the growth rate; excessive vitamin A in the ration decreased the growth rate of 12-month-old finishing steers. The marbling deposition decreased with the increment of vitamin A supplementation level, but possibly associated with vitamin A supplementing duration. Furthermore, the suitable dietary vitamin A level probably decreased lipid and pigment oxidation, and increased the tenderness of beef meat. Vitamin A supplementation had no significant effect on chemical composition of gluteus medius muscle and longissimus dorsi muscle.

Effect of early feed restriction on metabolic programming and compensatory growth in broiler chickens.

The effect of early feed restriction on metabolic programming and compensatory growth was studied in broiler chickens. A total of 480 female 1-d-old broiler birds (Aconred) were randomly allocated to ad libitum and feed-restricted groups, each of which was replicated 6 times with 40 birds per replicate. Broilers were provided commercial diets. Feed-restricted broilers were deprived of feed for 4 h per day from 1 to 21 d of age. Effects of treatments were determined at 21 and 63 d of age. In feed-restricted birds at 21 d of age, BW, average daily gain and average daily feed intake, breast muscle (P < 0.01), carcass yield (P < 0.05), and abdominal fat (P < 0.05) were decreased. Ether extract content in breast muscle was increased (P < 0.01), whereas CP content was slightly decreased. Triiodothyronine (P < 0.01) and thyroxine (P < 0.05) were decreased in serum. Free fatty acid and very low density lipoprotein were slightly increased in serum, whereas triglyceride and glucose were decreased (P < 0.01). Activities of NADPH-generating enzymes in liver including malic dehydrogenase, isocitrate dehydrogenase, and glucose-6-phosphate remained unchanged in ad libitum birds, whereas hormone-sensitive lipase activity was increased (P < 0.01). In feed-restricted birds at 63 d of age, BW, average daily gain, average daily feed intake, carcass yield, breast muscle yield, and serum triiodothyronine and thyroxine remained as ad libitum birds, whereas abdominal fat yield was increased (P < 0.05). Ether extract content in breast muscle was decreased (P < 0.01), whereas CP content was increased (P < 0.05). Activities of NADPH-generating enzymes were significantly increased, except abdominal malic dehydrogenase and hormone-sensitive lipase activity was decreased (P < 0.01) in liver and abdominal fat. Lipoprotein lipase activity was increased (P < 0.05) in abdominal fat. In summary, feed restriction severely affected growth performance and lipid metabolism in broilers in the early period. Because there was no statistical difference among the final BW, near full compensatory growth was achieved. In addition, early feed restriction might have induced prolonged metabolic programming in chicks and led to adult obesity.

Sampling procedure for the measurement of dissolved hydrogen and volatile fatty acids in the rumen of dairy cows.

Dissolved hydrogen (dH) influences the pathways of VFA production and is a precursor of methane formation in the rumen. Measurements of dH in rumen fluid taken at the same time as measuring other rumen fermentation end products would improve our quantitative understanding of the role of dH as a controller of rumen fermentation. Sample collections though a rumen cannula and using oral stomach tubing were compared for measurements of dissolved gases and fermentation end products in the rumen fluid of 4 ruminally cannulated dairy cows fed a total mixed ration of corn silage and concentrate. Rumen fluid was collected at 0, 2.5, and 6 h after morning feeding through the cannula from cranial dorsal rumen, cranial ventral rumen, central rumen, caudal dorsal rumen, and caudal ventral rumen and in parallel by oral stomach tubing at 2 insertion depths of 180 cm (sampling the central rumen) and 200 cm (sampling the caudal dorsal rumen). The cranial dorsal rumen had the greatest pH and smallest VFA concentration among 5 sites sampled. Samples collected by oral stomach tubing had greater ( < 0.001) rumen pH and less ( < 0.001) dissolved methane (dCH) and lower VFA concentration than that collected through rumen cannula. The dH concentrations were positively correlated ( > 0.8) in rumen samples collected by the 2 sampling techniques, with a concordance correlation coefficient larger than 0.8 and scale shift being about 0.1 away from unity. The variations in the measurement of dH, dCH, pH, and VFA in samples collected by oral stomach tubing are most likely the result of saliva contamination. The time of sampling relative to feeding had significant influence ( < 0.01) on dissolved gases and fermentation end products, with the greatest concentrations of dH, dCH, and VFA measured 2.5 h after morning feeding. The dH was correlated positively ( > 0.58) with dCH and negatively ( < -0.65) with the estimated net H production relative to the amount of VFA produced. This indicated that greater dH enhanced rumen CH production and also led to fermentation pathways that produce less H, such as enhanced propionate and butyrate production. In summary, oral stomach tubing could be a feasible method to measure ruminal dH in intact animals, but caution should be taken to minimize saliva contamination. Measurements made using both techniques yield similar conclusions for the effects of dH on fermentation pathways and CH generation.

Postnatal bacterial succession and functional establishment of hindgut in supplemental feeding and grazing goats.

The objectives of this study were 1) to investigate the age-related changes in functional achievement (establishment of fermentation capacity and enzyme activities) and bacterial succession (selected functional bacterial species) in the cecum and colon and 2) to assess the effect of feeding system (supplemental vs. grazing, Sup vs. G) on hindgut development in small ruminants. A total of 44 Liuyang black goat kids were randomly slaughtered at 0, 7, and 14 d of age (nonrumination period), 28 and 42 d of age (transition period), and 56 and 70 d of age (rumination period). Intestinal contents were sampled to determine VFA, activities of amylase, carboxymethylcellulase (CMCase), and xylanase, as well as abundances of total bacteria and selected functional bacterial species (genus Prevotella, cellulolytic and amylolytic bacteria) with quantitative PCR targeting the 16S rRNA subunit genes. Total VFA concentration (P < 0.01) and enzyme activities (P < 0.05) in hindgut contents were greater and total bacterial 16S rRNA gene copy numbers (P = 0.003) in the cecum were lower for Sup vs. G. Furthermore, irrespective of feeding system, hindgut total VFA concentrations and total bacterial 16S rRNA gene copy numbers increased with age (P < 0.01), with the greatest increase rate observed from 14 to 28 d. Amylase fluctuated with age, whereas CMCase and xylanase activities in Sup kids increased (P < 0.05) as age increased. The proportions of 16S rRNA copy numbers associated with the genus Prevotella and P. ruminicola increased (P < 0.05) with age, but those of cellulolytic bacteria and Ruminobacter amylophilus were detected only after 28 d of birth. The bacterial succession, fermentation capacity, and starch-degrading capacity in the hindgut of both groups were achieved at 1 mo, whereas fiber-degrading capacity in Sup kids was established at 2 mo of age; and supplemental feeding surpassed the grazing system in shaping hindgut development.

Effect of protein or energy restriction during late gestation on hormonal and metabolic status in pregnant goats and postnatal male offspring.

The objective of this study was to investigate the effects of maternal protein or energy restriction on hormonal and metabolic status of pregnant goats during late gestation and their postnatal male kids. Forty-five pregnant goats were fed a control (CON), 40% protein-restricted (PR) or 40% energy-restricted (ER) diet from 90 days of gestation until parturition. Plasma of mothers (90, 125 and 145 days of gestation) and kids (6 weeks of age) were sampled to determine metabolites and hormones. Glucose concentration for pregnant goats subjected to PR or ER was less (P < 0.001) than that of CON goats at 125 and 145 days of gestation. However, plasma nonesterified fatty acids concentration was greater (P < 0.01) at 125 and 145 days for PR and ER than CON. Protein restriction increased (P < 0.01) maternal cortisol concentration by 145 days of gestation, and ER decreased (P < 0.01) maternal insulin concentration at 125 days of gestation. Moreover, maternal amino acid (AA) concentrations were affected by nutritional restriction, with greater (P < 0.05) total AA (TAA) and nonessential AA (NEAA) for PR goats but less (P < 0.05) TAA and NEAA for ER goats at 125 days of gestation. After 6 weeks of nutritional recovery, plasma concentrations of most metabolic and hormonal parameters in restricted kids were similar to CON kids, except for reduced (P < 0.05) insulin concentration in ER, and reduced (P < 0.05) Asp concentration in PR and ER kids. These results provide information on potential metabolic mechanisms responsible for fetal programming.