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Context: Broiler chickens are exposed to various stressors, which can affect production performance. The use of dietary probiotics is one of the feasible methods to maintain performance, intestinal health, humeral immunity, and ameliorating physiological stress in the broiler. Aims: In all, 288 1-day-old male broiler chicks were used to evaluate the effect of probiotic supplementation on performance, morphology, and gene expression associated with immune responses in the starter phase of broiler chickens exposed to stress. Methods: In total, 288 1-day-old male broiler chicks (Ross 308) were assigned to evaluate the effects of Bacillus subtilis spore (BSS; Gallipro®200) supplementation at three levels (0, 0.8 × 105 colony-forming units (CFU) and 1.6 × 105 CFU/g feed) with corticosterone (CORT; 4 mg/kg BW at 7–9 days of age) or without CORT (oil) subcutaneous injection. The experiment was conducted in a completely randomised 2 × 3 factorial design. Key results: CORT injection and probiotic supplementation led to an increase and decrease respectively, in food conversion ratio compared with the control group (P < 0.05). CORT injections reduced the expression of TLR4, HSP70 and IgA in all parts of the intestine. However, the TLR4 gene expression increased in jejunum by CORT injections. BSS supplementation induced the expression of TLR4 in all sections of the intestine, both in stress and non-stress conditions. In stress-exposed chickens, IgA expression in the jejunum was affected by BSS supplementation. Interaction effects between CORT injections and BSS supplementation on the gene expression were significant in different parts of the intestine. Conclusions: Chicks exposed to stress conditions induced by CORT injection showed that the ileum was more susceptible than were the other parts, especially for TLR4 and HSP70 gene expression. BSS-supplemented birds showed more capability to face the stress condition, probably due to intestinal health and immunity-modulated effect of BSS. Implication: Formulating a ration with a probiotic can be more effective in stress conditions, through modulating immune-responsive genes in the intestine. The effects of various environmental stresses on the behavioral, physiological, and performance responses of birds have been studied for years. It has been shown that probiotics, also known direct-feed microbes, substantially influence nutrient digestibility, gut microflora and immunity, and inhibit pathogens and, ultimately, improve growth performance in broilers. Our findings suggested that formulating a ration with probiotic can be more effective in stress condition, with immune response genes modulating the effect in the intestine of broiler chicken. [ABSTRACT FROM AUTHOR]

Genetic parameters were estimated for objective and subjective traits assessed after 3 and 29 days aging in meat samples of 1154 commercial beef cattle. Meat attributes [Warner-Bratzler shear force (WBSF), intramuscular fat (IMF), and pH] and sensory traits [flavor intensity (FI), off-flavor (OF), connective tissue (CT), overall tenderness (OT), sustained juiciness (SJ), and overall palatability (OP)] were available. The animal mixed model used included additive genetic and residual effects as random effects, contemporary group as fixed effect and genomic breed composition and slaughter age as covariates. Genetic parameters were estimated using airemlf90 software and single-step genomic BLUP. Heritability estimates for OT (3 and 29 d), OP (3 d) and OF (29 d) were of moderate magnitude ranging from 0.18 ± 0.07 to 0.31 ± 0.07. Heritabilities were negligible or of low magnitude for all other sensory traits with values ranging from 0.03 ± 0.05 to 0.14 ± 0.07. Among objectively measured traits, the estimate of heritability for meat pH was moderate at day 3 (0.20 ± 0.08) and negligible at 29 (0.00 ± 0.05). For IMF and WBSF the heritability estimates were 0.43 ± 0.09 and 0.54 ± 0.09, and 0.22 ± 0.07 and 0.19 ± 0.07 for day 3 and 29, respectively. Genetic correlations between days for each sensory trait tended to be of high and positive magnitude ranging from 0.54 ± 0.60 to 0.99 ± 0.28. Genetic and phenotypic correlations of subjectively assessed traits were consistent in direction and magnitude with WBSF (negative) and IMF (positive) suggesting that genetic selection based on objectively measured traits can be used for meat quality improvement and to increase consumer satisfaction. In addition, selection can be implemented using sensory traits collected after 3 days of aging. • Heritability of both overall tenderness and palatability are suitable for genetic selection addressing consumer preference • Sensory panel traits measured at 3- and 29-days of aging are highly genetically correlated • Phenotypic records measured at day 3 of aging are suitable for genetic improvement of beef quality attributes • Genetic selection using objectively measured traits will lead to desirable genetic improvement for sensory panel traits [ABSTRACT FROM AUTHOR]