Splenic Gene Expression Signatures in Slow-Growing Chickens Stimulated in Ovo with Galactooligosaccharides and Challenged with Heat

Abstract

Galactooligosaccharides (GOS) that are delivered in ovo improve intestinal microbiota composition and mitigate the negative effects of heat stress in broiler chickens. Hubbard hybrids are slow-growing chickens with a high resistance to heat. In this paper, we determined the impact of GOS delivered in ovo on slow-growing chickens that are challenged with heat. The experiment was a 2 × 2 × 2 factorial design. On day 12 of incubation, GOS (3.5 mg/egg) was delivered into the egg (n = 300). Controls (C) were mock-injected with physiological saline (n = 300). After hatching, the GOS and C groups were split into thermal groups: thermoneutral (TN) and heat stress (HS). HS (30 °C) lasted for 14 days (days 36–50 post-hatching). The spleen (n = 8) was sampled after acute (8.5 h) and chronic (14 days) HS. The gene expression of immune-related (IL-2, IL-4, IL-6, IL-10, IL-12p40, and IL-17) and stress-related genes (HSP25, HSP90AA1, BAG3, CAT, and SOD) was detected with RT-qPCR. Chronic HS up-regulated the expression of the genes: IL-10, IL-12p40, SOD (p < 0.05), and CAT (p < 0.01). GOS delivered in ovo down-regulated IL-4 (acute p < 0.001; chronic p < 0.01), IL-12p40, CAT and SOD (chronic p < 0.05). The obtained results suggest that slow-growing hybrids are resistant to acute heat and tolerant to chronic heat, which can be supported with in ovo GOS administration.

Muscle Antioxidant Activity and Meat Quality Are Altered by Supplementation of Astaxanthin in Broilers Exposed to High Temperature

“…The welfare and growth of animals are adversely under influence of heat stress, which causes economic losses by increasing mortality and reducing feed intake [ 3 , 10 ]. Corticosterone can be an indicator of chronic stress and will be increased during stress [ 5 ].…”

“…A previous study also showed that dietary astaxanthin levels of 15 or 30 mg/kg cannot affect the gene expression of TNF- α in the liver of Pekin ducks [ 34 ]. In addition, down-regulation of anti-inflammatory cytokine IL-6 might suppress the induced inflammation from heat stress [ 3 ].…”

“…The continuous selection of broiler chickens for fast growth has increased their vulnerability to heat stress than other farm animals. High ambient temperature in summer is thus a serious stressor for broiler chickens, resulting in poor health status, welfare, growth, and carcass quality [ 1 , 2 , 3 , 4 , 5 ]. In addition to decreased growth performance, exposure of broiler chicks to heat stress increases the oxidative reactions that compromise meat quality by affecting ultimate pH, water-holding capacity, meat color, and meat tenderness [ 4 , 6 ], resulting in lower marketability.…”

Impact of Prebiotics and Synbiotics Administered in ovo on the Immune Response against Experimental Antigens in Chicken Broilers

“…Early in ovo supplementation with bioactive substances (on the 12th day of chicken embryo development) leads to the long-term maintenance of a high level of intestine bifidobacteria, reduces the number of detrimental microorganisms in the gut [13,17,18], modulates the central and peripheral lymphatic organ development in broilers [19], and stimulates gut-associated lymphoid tissues (GALT) development after hatching [20,21]. Galactooligosaccharides delivered in ovo mitigated heat-stress-induced chronic systemic oxidative stress and decreased the Th2 response in slow-growing chickens [22]. Selected synbiotics given in ovo can modulate the development of immune organs, e.g., the development of bursa of Fabricius and the spleen, and lymphocyte proliferation in the thymus [23,24], or downregulate the immune-related gene expression in the cecal tonsils and spleen in chickens [25].…”

Mucosal and Systemic Immune Responses Modulated by in Ovo-Delivered Bioactive Compounds in Distinct Chicken Genotypes

“…The most pronounced interaction in the systemic immune responses was down-regulation of the IL-12p40 mRNA abundance in the spleen of PRE/LPS/broilers (FC ~ -4.4). In our earlier studies we associated splenic mRNA abundance of IL-12p40 with responses to thermal stress in chicken broilers (12) and native chickens (13). Responses mounted by the immune system after acute or chronic exposition to heat stress resemble responses to LPS injected intraperitoneally into the body cavity.…”