Behavior and Immune Response of Conventional and Slow-Growing Broilers to Salmonella Typhimurium

Abstract

Fast growth rate in broiler chickens comes with welfare concerns and the contribution of growth rate to pathogen resistance and sickness behavior is relatively unknown. The objective of this study was to evaluate physiological and behavioral responses of conventional (CONV) and slow-growing (SG) male broilers challenged with Salmonella Typhimurium. CONV (n = 156) and SG (n = 156) chicks were raised in a pen with wood litter shavings until day 7 of age, when birds were transferred to 24 isolators (n = 11 chicks/isolator). On day 14 of age, half of the birds (n = 12 isolators) were challenged with S. Typhimurium (ST) and the other half (n = 12 isolators) received a control (C). On days 7, 13, 17, 21, and 24, body weight was recorded, and blood, jejunum and ileum sections were collected from 2 birds/isolator (n = 48 birds/sampling) to measure plasma IgA and IgG and intestinal histomorphology, respectively. On days 12, 16, 21, and 23, video was recorded to evaluate bird postures (sitting, standing, or locomoting) and behaviors (eating, drinking, preening, stretching, sham foraging, allopreening, and aggression). CONV birds were 70 g heavier (p = 0.03) on day 21 and 140 g heavier (p = 0.007) on day 24 than SG. On day 7, CONV jejunum villus height and crypt depth were 22 and 7 μm greater (p ≤ 0.001), respectively, than SG. On day 24, ST ileum villus height was 95 μm shorter (p = 0.009) than C. IgA increased after day 17 for all birds and at day 21, CONV IgA was greater (p = 0.01) than SG. Although SG IgG was 344 μg/ml greater (p = 0.05) than CONV on day 7, CONV IgG increased with age (p < 0.0001) to greater (p ≤ 0.03) concentrations than SG on day 21 and day 24 by 689 μg/ml and 1,474 μg/ml, respectively, while SG IgG remained at similar concentrations after day 13. Generally, a greater proportion of birds sham foraged as they aged (p < 0.0001). A greater proportion of CONV tended to sit (p = 0.09) and fewer locomoted (p < 0.0001) than SG as they aged. The results illustrate conventional and slow-growing broilers differ in their behavior, immunity, and response to Salmonella.

Ileal and cecal microbiota response to Salmonella Typhimurium challenge in conventional and slow-growing broilers

“…Therefore, the purpose of this study was to investigate the ileal and cecal microbiota response to Salmonella challenge in both conventional and slow-growing broilers. The behavior and immune response results from the broilers in this study have been published previously (Snyder et al, 2022).…”

“…On day 7, slow-growing broilers had lower diversity and richness in the ileum compared to fast-growing, conventional broilers. Not only was a change in the ileal microbiome observed, but on the same day, conventional broilers were found to have greater villus height and crypt depth in the jejunum based on a concurrent study, suggesting better intestinal health ( Snyder et al, 2022 ). Thus, the microbial communities between a slow-growing broiler and a conventional broiler may vary because of the difference in the morphology of the small intestines.…”

“…These results suggest that the microbiome of these two genetic lines are susceptible to Salmonella -induced dysbiosis at different times and intestinal locations. Further research is warranted to understand the specific immune response to Salmonella challenge in these broiler lines; it may be associated with the upregulation of genes related to T-cell activation in response to Salmonella challenge ( van Hemert et al, 2000 ) or that conventional broilers have significantly higher concentrations of IgA and IgG on day 21 ( Snyder et al, 2022 ).…”

Fowl Typhoid Outbreak on a Commercial Turkey Farm in Croatia

“…The prolonged pathogenesis of the infection may have also been affected by the birds’ age, breed, feed, husbandry system, infection time, and dose, or specific pathogen characteristics [ 18 , 19 ]. Besides the differences in the immune response to the infection among different broiler breeds, slow-growing breeds may have a different intestinal morphology [ 19 , 20 ] that influences the bacterial colonization of the gut.…”

An analysis of the welfare of fast-growing and slower-growing strains of broiler chicken

“…However, the majority of studies reviewed in this section provided both FG and SG strains a relatively low-energy diet in either experimental facilities (e.g. Nielsen, 2012;Sarica et al, 2014;Wallenbeck et al, 2016;Lichnikova et al, 2017;Rezaei et al, 2018;Ghayas et al, 2020, Ghayas et al, 2021Snyder et al, 2022;Wilhelmsson et al, 2019;Yngvesson et al, 2018) or on commercial farms (Castellini et al, 2016 (Supplementary Table 1)). In one study, the energy intake for the FG birds was even lower than that provided for SG birds (Lindholm et al, 2017).…”