Buffered formic acid and a monoglyceride blend improve performance and modulate gut bacteria and immunity gene expression in broilers under necrotic enteritis challenge.

Due to the removal of antibiotics from animal feed, alternatives have been sought to control necrotic enteritis (NE) in broilers. The current study investigated the effects of buffered formic acid (Amasil NA) and monoglycerides of short- and medium-chain fatty acids (Balangut LS P) on the performance and gut health of broilers challenged with NE. A total of 816 as-hatched 1-d-old chicks (Cobb 500) were randomly assigned to 6 treatments with 8 replicates. Treatments were: T1) nonchallenged control; T2) NE challenged control; T3) Amasil NA (challenge plus Amasil NA, 0.3% throughout all phases); T4) Balangut LS P (challenge plus Balangut LS P, 0.5%, 0.3%, and 0.2% in the starter, grower and finisher phases, respectively; T5) Combined (challenge plus combination of T3 and T4); T6) Antibiotic (challenge plus Zn bacitracin, 0.05 % throughout all phases). Birds were orally gavaged with live Eimeria vaccine species (d 9) and with Clostridium perfringens (d 14 and 15). On d 16, birds were sampled to evaluate gut permeability, microbiota, and mRNA abundance in the jejunum. The data were analyzed in JMP software using one-way ANOVA with Tukey's test to separate means, and Kruskal-Wallis test was used for non-normally-distributed parameters. Results showed that Balangut LS P decreased (P<0.05) feed conversion ratio compared to nonchallenged ones at the end of the study. Balangut LS P reduced (P < 0.05) the level of cecal Bacteriods compared to nonchallenged group, whereas Amasil NA shifted the levels of ileal Bifidobacteria, Enterobacteriaceae, and Lactobacillus towards nonchallenged control (P > 0.05). NE challenge upregulated (P < 0.001) the expression of IL-21R, zeta chain of T cell receptor (ZAP70), and dual specificity phosphatase 4 (DUSP4) compared to nonchallenged birds, whereas Balangut LS P showed an intermediate (P > 0.05) expression pattern of these genes towards nonchallenged and antibiotic groups. In conclusion, combination of Balangut LS P and Amasil NA has the potential to be used as an additive to improve the performance and gut health of broiler chickens, especially under challenging conditions such as NE infections.

Feeding recycled food waste improved feed efficiency in laying hens from 24 to 43 weeks of age.

There is renewed interest in utilizing food waste as animal feed due to its potential benefits in reducing feed cost and environmental impact while improving global food security. This study was conducted to examine the efficacy of recycled food waste-based feed for laying hen performance, egg quality, and nutrient digestibility. Hy-Line Brown hens (n = 150) were randomly distributed to three dietary treatments with 50 replicate cages of a single bird per treatment from 24 to 43 weeks of age. The treatments were: a standard/control feed based on wheat, sorghum, and soybean meal; a recycled food waste based-feed; and a 50:50 blend of control and food waste based-feed. Hens offered the food waste-based diets had similar egg weight, hen day egg production, and egg mass, but lower feed intake and higher feed efficiency, compared to those fed the control diets (P < 0.001). Hens fed the food waste diets exhibited lower shell breaking strength and shell thickness at week 34, and higher yolk color score and higher fat digestibility compared to the control treatment at week 43 (P < 0.001). Thus, feeding the recycled food waste based-feed maintained egg production while improving feed efficiency compared to the control feed.

Artificial gut and the applications in poultry: A review.

Artificial gut models including both the gastric and intestinal phases have been used in poultry research for decades to predict the digestibility of nutrients, the efficacy of feed enzymes and additives, and caecal fermentation. However, the models used in the past are static and cannot be used to predict interactions between the feed, gut environment and microbiome. It is imperative that a standard artificial gut model for poultry is established, to enable these interactions to be examined without continual reliance on animals. To ensure the validity of an artificial model, it should be validated with in vivo studies. This review describes current practices in the use of artificial guts in research, their importance in poultry nutrition studies and highlights an opportunity to develop a dynamic gut model for poultry to reduce the number of in vivo experiments.

Guanidinoacetic acid as a partial replacement to arginine with or without betaine in broilers offered moderately low crude protein diets.

Guanidinoacetic acid (GAA) is the direct precursor of creatine and can spare arginine (Arg) for creatine synthesis in low crude protein (CP) broiler diets. This study aimed to determine the extent GAA could spare Arg in broilers offered low CP diets and if supplemental betaine provides additional benefits. Seven hundred twenty-day-old Ross 308 male broilers were assigned into 9 dietary treatments with 8 replicates of 10 birds each. The treatments were; normal CP diet, a low CP (-15 g/kg) diet deficient in Arg, a low CP diet sufficient in Arg, and low CP diets with GAA, where 0.1% added L-Arg was spared by GAA at 50, 100, and 150% with and without 0.1% betaine. The treatments were offered during grower (d 10-24) and finisher (d 25-42) phases. The birds offered a low CP Arg deficient diet had 7.8% lower weight gain, 10 points higher FCR, 8.5% lower breast meat yield, 27.2% lower breast meat creatine concentration and 30.4% more abdominal fat pad compared to those offered a normal CP diet. When Arg was added back to the Arg deficient diet, growth performance, breast meat yield and creatine concentration loss were restored. When GAA spared Arg at 150%, feed intake, weight gain, FCR, breast and abdominal fat yields, breast meat moisture, drip loss, and breast meat creatine concentration became comparable to Arg sufficient low CP and normal CP treatments. When GAA spared Arg at 100 and 50%, FCR was 3 and 5 points lower than the normal CP treatment. Breast meat creatine concentration was positively correlated to feed efficiency (r = 0.70, P < 0.001) and breast meat moisture (r = 0.33, P < 0.01), and negatively correlated to relative weight of abdominal fat (r = -0.37, P < 0.01) and breast meat pH (r = -0.49, P < 0.001). There were no benefits of adding betaine with GAA on the parameters measured but the results with GAA were consistent in the presence or absence of betaine.

Potential of a mixture of eugenol and garlic tincture to improve performance and intestinal health in broilers under necrotic enteritis challenge.

Plant extracts (PE) are gaining increased attention as potential alternatives to in-feed antimicrobials (AM) due to their known antimicrobial activities. This study was conducted to examine the potential of PE, a microencapsulated product composed of eugenol and garlic tincture as an alternative to AM-agent on performance and intestinal health in broilers under necrotic enteritis (NE) challenge. A total of 960 day-old mixed-sex Cobb 500 chicks were randomly distributed to 48-floor pens with 6 treatments replicated 8 times with 20 birds each. The 6 treatments were as follows: UC, unchallenged control; CC, challenged control; PE, challenged group plus PE; AM, challenged group plus AM; FAP, challenged group plus a full dose of AM with PE; HAP, challenged group plus a half dose of AM with PE in starter, grower and finisher phases. Birds in the challenged groups were inoculated with Eimeria spp. on d 9 and Clostridium perfringens on d 14. The body weight gain (BWG), feed intake (FI), feed conversion ratio (FCR), and livability of birds were compromised, and intestinal lesions and mortality were increased (P < 0.05) by NE challenge, illustrating a successful clinical NE challenge. Birds fed AM had higher BWG and FI, and lower FCR, mortality, and intestinal lesions compared to the CC group (P < 0.05). Birds fed PE had improved FCR (P < 0.05) and livability (5.8%) in an overall period compared to the CC group. On d 16, PE supplementation reduced ileal lesion scores in only male birds (P < 0.05). Birds fed PE had decreased Eimeria maxima and Eimeria acervulina oocyst counts in caecal content (P < 0.05). Birds fed PE had decreased Escherichia brunetti and total oocyst counts in caecal content, and E. acervulina oocyst counts in ileal content in only female birds (P < 0.05). On d 35, PE supplementation reduced variation of BW in both male and female birds and increased yellowness (b∗ value, 14.4%) in the thigh. These findings suggest the potential of PE supplementation in diets to improve the performance and intestinal health of birds under clinical NE as indicated by improved FCR, livability, uniformity, reduced ileal lesions, oocyst counts and increased skin yellowness. However, the protective effect of PE may not be apparent in the presence of AM in the feed.

Effects of L-arginine and L-citrulline supplementation in reduced protein diets for broilers under normal and cyclic warm temperature.

Heat stress causes significant economic losses in the broiler industry. Dietary supplementation of arginine (Arg) and citrulline (Cit) might increase the performance of broilers raised under warm temperature due to vasodilation effects. This study investigated the effects of L-Arg or L-Cit supplementation in broilers fed a reduced protein wheat-based diet deficient in Arg under thermoneutral (NT) and cyclic warm temperature (WT). Ross 308 cockerels (n = 720) were randomly allocated to 4 dietary treatments with 12 replicates of 15 birds per pen from d 7 to 21. The 4 treatments were: normal protein (NP), i.e., 22.3% and 20.9% crude protein in grower and finisher, respectively; reduced protein (RP), i.e., 2.5% lower protein and deficient in Arg; and RP supplemented with 0.28% Arg (RP-Arg) or 0.28% Cit (RP-Cit). A factorial arrangement of treatments was applied during the finisher phase (21 to 35 d). Factors were: diet (4 diets above); and temperature, NT (24 °C) or cyclic WT (33 ± 1 °C for 6 h per day) with 6 replicate pens per treatment. During 7 to 35 d and 21 to 35 d, the birds fed the RP diet had lower body weight gain (BWG) and higher FCR compared to the NP diet (P < 0.01). The addition of Arg or Cit to RP decreased FCR compared to RP (P < 0.01). During 21 to 35 d, the birds exposed to WT had lower feed intake (FI), lower BWG (P < 0.001) but similar FCR (P > 0.05) compared to birds exposed to NT. Diet by temperature interactions were not observed for performance parameters during the period of WT (P > 0.05). On d 35, the RP-fed birds had a lower yield of thigh and drumstick, higher fat pad, lower femur ash, and breaking strength but similar serum uric acid level and higher nitrogen digestibility on d 21 compared to those offered NP (P < 0.05). Supplementation of Arg or Cit to RP resulted in increased femur ash on d 35 (P < 0.05). Thus, feeding the NP diets is necessary to maintain growth performance in broilers regardless of the temperature conditions.

In vitro inhibitory activities of sugarcane extract on avian Eimeria sporozoites.

The current in vitro study aimed to investigate the effects of a processed sugarcane extract on the viability of avian Eimeria sporozoites. Treatments were applied to hatched sporozoites: 1) without additives (no-treatment control); 2) with ethanol; 3) with salinomycin; 4) with Polygain™. All treatments were incubated in RPMI media containing live sporozoites at 37 °C for 14 h and then the number of viable sporozoites were counted. Compared to the no-treatment control, Polygain™ decreased (P < 0.001) the counts of E. maxima, E. acervulina, E. bruneti, and E. mitis sporozoites to a level similar to salinomycin (P > 0.05). In conclusion, Polygain™ could be a potential candidate as an anticoccidial agent.

Response of laying hens to l-arginine, l-citrulline and guanidinoacetic acid supplementation in reduced protein diet.

A study was conducted with Hy-Line Brown laying hens to examine the effects of reduced protein diet, deficiency of arginine (Arg), and addition of crystalline Arg, citrulline (Cit) and guanidinoacetic acid (GAA) as substitutes for Arg. Hen performance, egg quality, serum uric acid, liver and reproductive organ weights, and energy and protein digestibility were measured using a completely randomized design with 5 treatments. Treatments were a standard diet (17% protein diet; SP), a reduced diet (13% protein diet deficient in Arg; RP) and RP with added Arg (0.35%, RP-Arg), GAA (0.46% equivalent to 0.35% Arg, RP-GAA) or Cit (0.35%, RP-Cit) to the level of SP. It was hypothesized that performance would decrease with Arg deficient RP diet and the addition of GAA or Cit in RP would allow birds to perform similar or greater than Arg-added RP treatment. The experiment was conducted from 20 to 39 wk of age but the treatment effect was seen only after 29 wk of age. The birds offered RP had reduced egg and albumin weights (P < 0.01), lower yolk color score (P < 0.01), lower protein intake and excretion (P < 0.01) than those offered SP. When Arg or Cit were added to RP to make them equivalent to SP, feed intake (FI) and egg production were not different than those of RP (P > 0.05). The birds offered RP-GAA decreased FI and egg production (P < 0.01) compared to those offered RP. The addition of Arg, Cit or GAA to the RP had no effect on egg quality parameters, protein and energy digestibilities (P > 0.05). However, birds offered the RP-Cit diet tended to have higher Haugh unit (P = 0.095) and lower shell breaking strength (P = 0.088) compared to all other treatments while those offered RP-GAA had higher energy digestibility (P < 0.05) than all other groups but RP. The limited performance response of hens fed RP with added Arg, GAA, or Cit may be due to deficiency of some other nutrients in RP such as phenylalanine, potassium or non-essential amino acids and other components of soybean meal in the diet.

Net energy, energy utilization, and nitrogen and energy balance affected by dietary pea supplementation in broilers.

Pea starch consists predominantly of C-type of amylopectin chain which is more resistant to digestive enzymes than A-type of starch thus slowly digested in poultry. It was hypothesized that the presence of slowly digested pea starch in broiler diets will increase net energy and the efficiency of energy utilization in broilers. Two experiments were performed to investigate starch digestibility of pea at different incubation times (in vitro study) and the effect of dietary pea on heat increment and net energy in broilers using an open-circuit respiratory calorimetry system (in vivo study). One-day-old Ross 308 male broilers were fed a common starter crumble from d 1 to 10 and standard grower diets thereafter. At d 21, birds were transferred to the chambers each housing 2 birds. Each treatment was replicated 6 times with 2 identical runs of 3 replicates per treatment. A wheat-soybean meal-based diet was used as a control and the treatment diet contained 500 g of pea/kg pea. In vitro study showed that pellet processing increased (P < 0.001) starch digestibility, particularly at shorter times for wheat and a much larger response for pea. Birds offered the pea-based diet had lower (P = 0.002) feed intake, lower (P = 0.020) body weight gain, but a similar (P > 0.05) FCR compared to those offered the wheat-based diet. Net energy (NE) and apparent metabolizable energy (AME) values were higher in the pea-based diet than in the wheat-based diet (P = 0.037 for NE and P = 0.018 for AME). Heat production, respiratory quotient, heat increment of feed, efficiency of utilization of gross energy for AME, and efficiency of utilization of AME for NE did not differ (P > 0.05) between the 2 treatments. There was no effect (P > 0.05) of pea on the total tract digestibilities of dry matter, crude protein and ash, but the total tract digestibility of starch was higher (P = 0.022) in the pea-based diet compared to the wheat-based diet. This study provides insight into the energy metabolism of broilers offered a pea-based diet and indicates that dietary pea supplementation increases dietary AME and NE but has no effect on heat increment of feed and the efficiency of energy utilization in broilers.

Response of meat chickens to different sources of arginine in low-protein diets.

Arginine activity in broiler diets can be supplied by L-arginine (Arg), guanidinoacetic acid (GAA) and L-citrulline (Cit), all of which are commercially available. This study was conducted to assess the effects of Arg source and level on broiler performance, nutrient digestibility and carcass parameters. Day-old Ross 308 cockerels (n = 768) were assigned to one of eight dietary treatments using a completely randomized design: normal protein (NP), low protein deficient in Arg (LP) and LP with two levels of either Arg (0.238% and 0.476%), GAA (0.309% and 0.618%) or Cit (0.238 and 0.476%). The LP was 5 percentage points lower in protein level than the NP. Wheat, sorghum, soya bean meal, canola meal, and meat and bone meal-based diets were fed over three feeding phases to 6 replicate floor pens with 16 birds each. Compared to NP, birds fed LP had reduced feed intake (FI, p < 0.001), reduced body weight gain (BWG, p < 0.001) and increased feed conversion ratio (FCR, p < 0.001) from day 0 to day 35. Additions of Arg or Cit to the LP at both levels resulted in increased BWG and reduced FCR (p < 0.05). Birds fed LP with GAA added had lower FCR (p < 0.05) but not higher BWG (p > 0.05) compared with the LP observed from day 0 to day 35. Supplementation of Arg, Cit and the low level of GAA to LP resulted in increased carcass yield, bone length, diameter and ash (p < 0.05) but did not increase ileal energy or nitrogen digestibility (p > 0.05). The findings indicate that Cit is an efficacious source of Arg activity in Arg-deficient diets.

Detection of Ascaridia galli infection in free-range laying hens.

Reliable methods for detection of A. galli infection using excreta egg count (EEC) and ELISA assays to determine A. galli specific IgY levels in serum and yolk samples were compared from hens infected naturally and artificially. Artificially infected hens were used to generate samples for analysis of preferred detection methods and to generate contaminated ranges for use in the naturally acquired infection study in which Lohmann Brown hens (n = 200) at 16 weeks of age were randomly assigned to four treatments with five replicate pens. Hens of negative control (NC) ranged on a decontaminated area, hens of low infection, medium infection and positive control (PC) ranged on the areas previously contaminated by hens artificially infected with 250, 1000 and 2500 A. galli eggs/hen, respectively. Additionally, hens of PC were orally infected with 1000 A. galli eggs/hen. Anti A. galli antibody levels in hen serum (SIgY) and yolk (YIgY) were measured before range access, and 2, 7 and 12 weeks after access to the contaminated ranges. In a natural infection study, eggs were detected in the excreta of all hens 4 weeks after range access, with the exception of NC in which no eggs were detected. EEC increased to reach maximum value (2204 ±â€¯307 eggs/g) after 11 weeks of range access and then declined at 12 weeks (905 ±â€¯307eggs/g) (p < 0.01). While SIgY OD values were not different in hens between any groups before range access, after 2 weeks, both SIgY and YIgY gradually increased in hens of PC (1.17 ±â€¯0.03 and 0.88 ±â€¯0.04) and medium infection (1.07 ±â€¯0.03 and 0.96 ±â€¯0.04) compared to low infection (0.38 ±â€¯0.03 and 0.29 ±â€¯0.04) (p < 0.01) and NC. After 12 weeks, SIgY were similar in hens of PC, medium and low groups whereas YIgY was higher in hens of low infection group (p < 0.01). Sensitivity of the serum and egg yolk antibody levels assay to detect A. galli infection was 100% and 96%, respectively, whereas the pooled EEC method yielded a sensitivity of 93%. The results of this study suggest that hens naturally infected with A. galli produce both SIgY and YIgY at different levels depending on the infection intensity and duration of exposure which allows the diagnosis of prior infection or early diagnosis of current infection. Use of the practical and non-invasive method of yolk sample analysis for detecting IgY can be just as informative as using serum samples to detect A. galli infection.

Dietary energy, digestible lysine, and available phosphorus levels affect growth performance, carcass traits, and amino acid digestibility of broilers.

A 3-factor, 3-level Box-Behnken design was used to investigate the interaction effect of dietary digestible lysine (dLys, 9.5, 10.5, 11.5 g/kg), apparent metabolizable energy (AMEn, 12.77, 13.19, 13.61 MJ/kg) and available P (avP, 3.0, 4.0, 5.0 g/kg) levels on performance and amino acid (AA) digestibility of Ross 308 male broilers (n = 1,050) from d 14 to 34. The design consisted of 15 treatments each replicated 5 times with 12 birds per replicate. On d 34, 3 birds were sampled from each pen to collect ileal digesta (pooled per pen) to analyze AA. Response surface was fitted by first-, second-, or third-degree polynomial regressions in JMP statistical software v. 12.0.1. Feed intake (FI), weight gain (WG) and feed conversion ratio (FCR) were affected by dLys (linear and quadratic, P < 0.01), AMEn (linear, P < 0.01) and AMEn × avP (P < 0.01). Increased dLys increased FI but increased AMEn decreased FI in the birds fed the low-avP diet. However, when the avP level in the diet was increased, FI decreased to 13 MJ/kg AMEn and remained constant thereafter. Increased dLys increased WG whereas an increase in AMEn decreased WG in the birds fed the low-avP diet but had no effect on WG in those fed the high-avP diet. Increased dLys decreased FCR whereas increased AMEn decreased FCR in the birds fed the low-avP diet but had no effect on FCR in those fed the high-avP diet. Increased dLys increased breast yield percentage (linear, P < 0.01 and quadratic, P < 0.05) whereas increased AMEn decreased breast yield percentage (linear, P < 0.01). Dietary levels of dLys or avP had positive, linear effects on apparent ileal digestibility (AID) of methionine (P < 0.01) and threonine (P < 0.01) but had no effect on other AA (P > 0.05). These results indicate that increasing dLys levels above current industry standard would improve broiler performance irrespective of AMEn or avP levels of the diet.

Necrotic enteritis challenge and high dietary sodium level affect odorant composition or emission from broilers.

Necrotic enteritis (NE) challenge and high dietary sodium (from sodium chloride) level on odor flux from broiler litter was investigated using 160 day-old Ross 308 male chicks randomly assigned to 4 dietary treatments with 4 replicates of 10 birds each. A 2 × 2 factorial arrangement of treatments was employed. Factors were: presence or absence of NE challenge and normal (1.6 g/kg) or high (4.0 g/kg) dietary sodium (Na) level. On d 20, odorants were collected from litter headspace with a flux hood and measured using selected ion flow tube mass spectrometry (SIFT-MS). On d 33, while challenge did not lead to higher mortality, it reduced feed intake by 5.48% (P < 0.05) and body weight gain by 9.02% (P < 0.01) and worsened FCR by 5 points (P < 0.01), indicating subclinical necrotic enteritis occurred in challenged birds. Challenge increased (P < 0.01) litter moisture and litter headspace concentrations of dimethyl sulfide (P < 0.05), propyl mercaptan (P < 0.05), total butanols (P < 0.05), acetoin (P < 0.01), skatole (P = 0.05), butyric acid (P < 0.05), and methyl amine (P < 0.05) and tended to increase concentrations of ethyl mercaptan (P = 0.07), carbon disulfide (P = 0.09), indole (P = 0.10), and formic acid (P = 0.10) compared to the unchallenged group. The birds fed a high Na diet produced higher litter moisture (P < 0.01) and higher litter headspace concentration of sulfur compounds and phenol (P < 0.01) compared to those fed a normal Na diet. In the birds fed a high Na diet, challenge increased the litter flux of some additional odorants, which included 2,3-butanedione (P < 0.05), acetic acid (P < 0.01), propionic acid (P < 0.01), isobutyric acid (P < 0.01), isovaleric acid (P < 0.01), pentanoic acid (P < 0.05), 2-butanone (P < 0.05), and 3-methyl-1-butanol (P < 0.05). These findings suggest that both a high Na diet and sub-clinical NE increase the odor nuisance potential of broiler farms.

Emissions of volatile odorous metabolites by Clostridium perfringens - in vitro study using two broth cultures.

An in vitro study was carried out to investigate the volatile odorous metabolites produced by necrotic enteritis inducing Clostridium perfringens (Cp) type A field strain (EHE-NE18) cultured in two broth media (thioglycollate broth, brain heart infusion broth) at three levels (0, 103 cfu/mL, 106 cfu/mL) using 2 × 3 factorial arrangement of treatments, with each replicated three times. The culture media with and without Cp was freshly prepared on the day of measurement and the culture headspace concentration of odorants was measured using selected ion-flow tube mass spectrometry (SIFT-MS). The results showed that media type and Cp level affected the concentration of a range of volatile odorous metabolites including sulfur compounds, alcohols, ketones, amines, and carboxylic acids. Thus, Cp contributes to the production of a wide range of odorous metabolites that can impart noxious smell during infection.

Influence of feeding crimped kernel maize silage on the course of subclinical necrotic enteritis in a broiler disease model.

This experiment was carried out with 375 male broilers (Ross 308) from days 1 to 28 to evaluate the influence of crimped kernel maize silage (CKMS) on the manifestation of subclinical necrotic enteritis, microbiota counts, organic acid production and relative weights of gastrointestinal segments. A necrotic enteritis disease model was applied. Birds were allocated into 3 different dietary treatments: a maize-based feed (MBF, control diet), and 2 diets supplemented with 15% (CKMS15) or 30% (CKMS30) of crimped ensiled kernel maize. The disease model involved a 10-time overdose of an attenuated live vaccine against coccidiosis given orally on day 17, followed by oral inoculation of Clostridium perfringens Type A (S48, 108 to 109 bacteria/bird) twice daily on days 18, 19, 20 and 21. Scoring of intestinal lesions was performed on days 22, 23, 25 and 28. Ileal and caecal digesta samples were collected for the quantification of selected bacterial groups and organic acids. The results showed that there was no effect of dietary treatments on small intestinal lesion scores (P > 0.05). Lesions scores peaked on days 23 and 25 and decreased again on day 28 (P = 0.001). No effect of age on microbiota counts was observed, but feeding of CKMS30 reduced the number of coliforms in ileal contents (P = 0.01). Dietary treatments did not affect organic acid concentrations in ileum and caeca, but there was an effect of age; butyric acid was higher on days 22, 23 and 25 than on day 28 (P = 0.04). Acetic acid and propionic acid concentrations in caeca were the highest on days 22 and 28 but the lowest on days 23 and 25. Relative gizzard and caeca weights were increased, and relative ileum weights were decreased when birds were fed CKMS30 (P < 0.05). In conclusion, the inclusion of CKMS in broiler diets had no effects on the course of necrotic enteritis but had potential benefits in terms of inhibition of potentially harmful microorganisms.

Characterisation and quantification of changes in odorants from litter headspace of meat chickens fed diets varying in protein levels and additives.

The effect of dietary crude protein (CP) and additives on odor flux from meat chicken litter was investigated using 180 day-old Ross 308 male chicks randomly allocated to five dietary treatments with three replicates of 12 birds each. A 5 × 3 factorial arrangement of treatments was employed. Factors were: diet (low CP, high CP, high CP+antibiotic, high CP+probiotic, high CP+saponin) and age (15, 29, 35 days). The antibiotic used was Zn bacitracin, the probiotic was a blend of three Bacillus subtilis strains and the saponin came from a blend of Yucca and Quillaja. Odorants were collected from litter headspace with a flux hood and measured using selective ion flow tube mass spectrometry (SIFT-MS). Litter moisture, water activity (Aw), and litter headspace odorant concentrations were correlated. The results showed that low CP group produced lower flux of dimethyl amine, trimethyl amine, H2S, NH3, and phenol in litter compared to high CP group (P < 0.05). Similarly, high CP+probiotic group produced lower flux of H2S (P < 0.05) and high CP+saponin group produced lower flux of trimethylamine and phenol in litter compared to high CP group (P < 0.05). The dietary treatments tended (P = 0.065) to have higher flux of methanethiol in high CP group compared to others. There was a diet × age interaction for litter flux of diacetyl, 3-hydroxy-2-butanone (acetoin), 3-methyl-1-butanol, 3-methylbutanal, ethanethiol, propionic acid, and hexane (P < 0.05). Concentrations of diacetyl, acetoin, propionic acid, and hexane in litter were higher from low CP group compared to all other treatments on d 35 (P < 0.05) but not on d 15 and 29. A high litter moisture increased water activity (P < 0.01) and favored the emissions of methyl mercaptan, hydrogen sulfide, dimethyl sulfide, ammonia, trimethyl amine, phenol, indole, and 3-methylindole over others. Thus, the low CP diet, Bacillus subtilis based probiotic and the blend of Yucca/Quillaja  saponin were effective in reducing the emissions of some key odorants from meat chicken litter.

Performance, litter quality and gaseous odour emissions of broilers fed phytase supplemented diets.

The effect of graded levels of phytase on performance, bone characteristics, excreta/litter quality and odorant emissions was examined using 720 Ross 308 male d-old broilers. A 2 × 4 factorial arrangement of treatments was employed with 6 replicates of 15 birds per pen. Factors were: diets-positive and negative control (PC, NC); phytase - 0, 500, 1,000, 1,500 FTU/kg. The PC was formulated to meet the 2014 Ross 308 nutrient specifications, whereas the NC was formulated with lower Ca (-1.4 g/kg), available P (-1.5 g/kg), Na (-0.3 g/kg), dLys (-0.2 g/kg) and MEn (-0.28 MJ/kg) equivalent to nutrient matrix values for 500 FTU/kg phytase in the starter, grower and finisher periods (i.e., downspec diet). On d 24, phytase decreased FCR by 1.6, 4.3 and 4.6 points at inclusion levels of 500, 1,000 and 1,500 FTU/kg, respectively (P < 0.01) across all diets. Phytase by diet interactions on BW gain were observed on d 24 and 35 (P < 0.01). The effect of phytase was much more pronounced in the NC diet as compared with the PC diet. On d 24, phytase increased BW gain by 37, 55 and 68 g in the PC and 127, 233 and 173 g in the NC at 500, 1,000 and 1,500 FTU/kg, respectively. Diet by phytase interactions were also observed for tibia ash, litter quality and water to feed intake ratio (P < 0.01) with higher phytase effect in NC as compared with PC. Neither diet nor phytase impacted excreta moisture content on d 18 or 21 (P > 0.05). Solid phase micro-extraction gas chromatography-mass spectrometry (SPME-GC-MS) analysis of gaseous emissions on d 39 indicated no difference in the emission of alcohols, aldehydes, ketones, volatile fatty acids and phenols between treatments (P > 0.05). The results indicate that phytase has greater benefits when formulated using nutrient matrix values as compared with adding it over the top in an already nutrient sufficient diet. The later method would be expected to increase feed costs without concomitant performance benefits.

Dietary composition affects odour emissions from meat chickens.

Abatement of odour emissions has become an important consideration to agricultural industries, including poultry production. The link between diet and odour emissions was studied in two experiments using Ross 308 male meat chickens reared in specially designed chambers in a climate controlled room. In the first experiment, two treatments were compared using three replicates of two birds per chamber. Two wheat-soy based treatment diets were formulated with or without canola seed, an ingredient rich in sulfur amino acids. Treatment 1 (T1) had 13.39 MJ/kg ME (as fed) and used 60 g/kg canola seed without corn while Treatment 2 (T2) contained 12.90 MJ/kg ME (as fed) and used 150 g/kg corn without canola seed. In the second experiment, birds were assigned to three dietary treatments of five replicates with five birds per replicate (chamber). The basal starter, grower and finisher diets in the control group (SBM group) contained soybean meal in the range of 227-291 g/kg (as fed) as the main protein source. The other treatments (CM and MBM groups) contained either high levels of canola meal (174-190 g/kg) or meat meal (74-110 g/kg) at the expense of soybean meal. In both experiments, diets were isocaloric, isonitrogenous and contained similar digestible amino acid contents as per 2007 Aviagen Ross 308 guidelines. Emissions of odour were measured using Fourier transform infrared (FTIR) spectroscopy. In both experiments, major odorous compounds detected included 2,3-butanedione (diacetyl), 2-butanone, dimethyl disulfide, methyl mercaptan, ethyl mercaptan, 2-butanol, 3-methyl-butanal, phenol and m-cresol. In the first experiment, T1 (with canola seed) produced higher concentration of methyl mercaptan (P < 0.05) and lower diacetyl (P < 0.01) than T2. In the second experiment, methyl mercaptan emission was higher in SBM group (P = 0.01) and total elemental sulfur were higher in SBM and CM groups up to day 24 (P < 0.01). Results of these experiments indicated a direct link between diet and odour emissions from meat chickens.