The gut microbiota of chicken has received much attention due to its importance for bird health, food safety, and performance. In the United States, the impending transition to cage-free housing environments has raised many questions about its consequences for poultry health, productivity, and welfare. Therefore, we investigated how housing environments and feed composition affect the poultry gut microbiome. Such data is necessary to inform the design of production systems that promote health and food safety. In this study, we investigated the cecal microbiome of both caged and cage-free laying hens that were fed either an industry-standard soy-based versus a soy-free diet. Caged hens were housed in standard industry-style layer cages with one bird per cage, and cage-free hens were housed in a poultry barn with an outdoor enclosed yard with multiple hens per pen. Our study showed significant differences in the gut microbiota between cage-free and caged environments. Cage free housing generated higher diversity compared to caged housing. Furthermore, we observed a synergistic interaction of soy-based feed in cage-free housing, as the cage-free soy group showed the highest alpha diversity, whereas the caged-soy group showed the lowest diversity overall.

Plasma and tissue concentrations of total, (+)- and (-)-gossypol were determined in broilers fed cottonseed meals (CSM) from eight oil mills (five expander solvent, two expeller, and one direct solvent). Free gossypol in the meals ranged from 0.033 to 0.180%, and total gossypol ranged from 0.974 to 1.459%. The (+)-enantiomer of gossypol varied from 53.8 to 61.3% of total gossypol. Eight CSM diets containing 28% CSM and a soybean meal control diet were fed to 162 1-d-old male broiler chicks during a 3-wk starter period. Concentrations of free gossypol in the CSM diets ranged from 92 to 504 μg/g, and total gossypol ranged from 2,626 to 4,085 μg/g. All diets were formulated with the same concentrations of digestible lysine and methionine and were fed ad libitum. At 21 d of age, there were no significant differences in body weights, feed conversions, or mortality of birds fed the CSM diets when compared to birds fed the soybean meal diet. Concentrations of (+)- and (-)-gossypol in plasma, liver, kidney, and muscle increased linearly as the level of free gossypol increased in the diets. Liver had the highest concentration of total gossypol (71.4 to 313.6 μg/g DM) followed by kidney (9.2 to 36.3 μg/g DM), plasma (3.0 to 14.6 μg/mL), and muscle (2.1 to 9.8 μg/g DM). The proportion of (−)-gossypol was higher in plasma (26.7%) and kidney (25.6%) than in muscle (19.1%) and liver (16.0%). Performance data from this study indicate CSM can be used successfully in chick starter diets at levels up to 28% when diets are formulated on a digestible amino acid basis.

This experiment was designed to evaluate the use of expander cottonseed meal (CSM) in broiler diets formulated on a digestible amino acid basis and to determine the tissue distribution of gossypol enantiomers and their relationship to gossypol consumption. Gossypol is an antinutritional polyphenolic pigment found in cottonseed. A total of 800 1-d-old broilers (Arbor Acres) was randomly divided into 40 groups of 20 birds each and placed in a broiler house with wood shavings litter. The CSM was included in starter and grower diets at 0, 7, 14, 21, and 28% of the diet. Diets were formulated to have similar levels of digestible methionine and lysine as the 0% CSM control diet. At 21 d of age, five birds per pen were randomly selected for the determination of gossypol enantiomers in plasma, liver, heart, and breast muscle. Tissues were again collected at 42 d of age. Results of this experiment indicated that at 21 d of age cumulative body weight and feed-to-BW ratios of birds fed CSM diets were not significantly different from the control. By 35 d of age, feed-to-BW ratios of experimental birds fed the 28% CSM diet were significantly greater than the control birds, and by 42 d, BW were lower than those of the control group. Tissue concentrations of total, (+) and (−) gossypol increased linearly as the level of CSM increased. At 42 d, liver had the most gossypol with a ratio of 87% (+) gossypol to 13% (−) gossypol. Plasma contained 73% (+) gossypol and 27% (−) gossypol. Heart contained 45% (+) gossypol and 55% (−) gossypol. Breast muscle had the least gossypol. Results of this experiment indicated that expander solvent CSM could be fed to broilers at up to 21% of the total diet if amino acid digestibility was considered.

To evaluate the effect of L-Threonine (L-Thr) and Mycofix^® Plus (MP) on aflatoxicosis, an experiment with a 3-way ANOVA model was carried out with 8 replicates and 640 birds. Treatments included two levels of L-Thr (100% and 125% of the requirements, Cobb 500, Cobb-Vantress), Aflatoxin B₁ (AFB₁) (0, 500 ppb), and MP (0, 1 g/kg). As the main effects showed, AFB₁ decreased breast meat yield and carcass percentage (p < 0.001), serum urea, antibody titer against infectious bronchitis virus (IBV), and bone density (p < 0.05), while it increased the plasma concentrations of glucose and alkaline phosphatase (ALP) (p < 0.05). Mycofix Plus improved the grower feed intake (FI), tibia fresh weight, and body weight (BW) to bone weight (p < 0.05). L-Threonine increased the grower FI, breast meat yield, serum aspartate transaminase (AST), and glutathione peroxidase (GPX) (p < 0.05). There were positive interactions with breast meat yield, cholesterol, lactate dehydrogenase (LDH), and IBV titer. Of the treatments used, the combination of L-Thr and MP without AFB₁ improved breast meat and carcass percentage. L-Threonine and MP significantly improved IBV titer in birds challenged with AFB₁ (p < 0.001). In conclusion, L-Thr and MP were beneficial to improve immunity.

The present study aimed to show the benefits of novel lactic acid bacteria (LAB) strains isolated from the caeca of healthy chickens. These novel strains, identified as Limosilactobacillus reuteri and Ligilactobacillus salivarius, displayed high levels of lactic acid production, capability of biofilm formation, high aggregation and adhesion scores, and significant survival rates under conditions mimicking the chicken gastrointestinal tract (GIT). In addition, these novel Lactobacillaceae isolates were neither hemolytic nor cytotoxic. In vivo trials were able to establish their ability to reduce necrotic enteritis. Notably, a significant weight gain was registered, on day 10 of treatment, in the group of chickens fed with a mixture of L. reuteri ICVB416 and L. salivarius ICVB430 strains, as compared with the control group. This group has also shown a reduced number of lesions in the gut compared with other infected chicken groups. This study provides in vitro and in vivo evidence supporting the benefits of these novel Lactobacillaceae isolates for their use in poultry livestock as protective cultures to control the bacterial necrotic enteritis (NE) Clostridium perfringens.