Impact of galactooligosaccharides delivered in ovo on mitigating negative effects of heat stress on performance and welfare of broilers

Abstract

Galactooligosaccharides (GOS) delivered in ovo improve intestinal health of broiler chickens. This study aimed to demonstrate the impact of in ovo stimulation with GOS prebiotic on day 12 of egg incubation on performance and welfare traits in broiler chickens. The incubating eggs were divided into 3 groups, based on the substance injected in ovo: 3.5 mg of GOS dissolved in 0.2 mL physiological saline (GOS), 0.2 mL physiological saline (S), or uninjected controls (C). Constant heat stress (HS) was induced on days 32 to 42 post-hatch by increasing environmental temperature to 30°C. Thermoneutral (TN) animals were kept at 25°C. The performance (body weight [BW], daily feed intake [DFI], daily weight gain [DWG], and feed conversion rate [FCR]) were measured and mortality was scored for starter (days 0 to 13), grower (days 14 to 27), and finisher (days 28 to 42) feeding phases. Rectal temperature was scored on days 32 to 42. Food-pad dermatitis (FPD) was scored post-mortem (day 42). GOS increased ( P < 0.01) BW on day 42 (2.892 kg in GOS vs. 2.758 kg in C). Heat stress significantly reduced ( P < 0.01) final BW (2.516 kg in TN vs. 3.110 kg in HS). During finisher phase, DFI was significantly higher in GOS vs. C (173.2 g vs. 165.7 g; P < 0.05). FCR calculated for the entire rearing period (days 0 to 42) ranged from 1.701 in C to 1.653 in GOS ( P < 0.05). GOS improved FCR in HS animals during finisher phase ( P < 0.05). Rectal temperature of GOS chickens under HS reached 42.5°C 1 day earlier than C and S ( P < 0.05), which suggests that those birds recovered earlier from the high environmental temperature. Heat stress increased ( P < 0.05) mortality about 5 times compared to TN during finisher phase (from 1.59% in TN to 7.69% in HS). GOS decreased FPD in TN conditions by 20% (no lesions in 81% in GOS vs. 60% in C). GOS delivered in ovo mitigated negative effects of HS on performance and welfare in broiler chickens.

Heat Treatment at an Early Age Has Effects on the Resistance to Chronic Heat Stress on Broilers

“…Studies conducted by Yalcin et al [8] showed that 3 weeks of heat treatment (32 to 35 • C/7 h/day) reduced the body weight gain in chickens. A previous study reported that in ovo injection of galactooligosaccharides could maintain the body weight during heat stress [19]. However, the CH and HH groups showed a lower body weight gain than the control group, that showed the early heat exposure have no effect on body weight (Table 4).…”

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

“…On a performance level, HS causes losses in feed intake and growth rate. In broiler chickens, chronic HS has been found to significantly reduce (p < 0.01) final body weight (BW) (2.52 kg in TN vs. 3.11 kg in HS) [32,39,40]. In the current study, chronic HS also reduced final BW (p < 0.001), but the difference between TN and HS was almost two times lower than in broiler chickens (2.21 kg in TN vs. 1.94 kg in HS), even with the longer rearing period (42 days in broilers vs. 50 days in slow-growing chickens).…”

“…Galactooligosaccharides are potent prebiotics that exert beneficial effects on intestinal microbiota in chickens. Particularly interesting is the possibility of using in ovo technology for the early stimulation of the microbial communities with GOS [32,39,40]. The molecular data on broiler chickens have indicated that HS triggers systemic immune and stress responses, which are balanced by GOS that are delivered in ovo [41].…”

“…The molecular data on broiler chickens have indicated that HS triggers systemic immune and stress responses, which are balanced by GOS that are delivered in ovo [41]. It also mitigates the negative effects of HS in broiler chickens on performance traits, including improved growth efficiency, feed efficiency [39], and meat quality [10]. In this study, we focused on chickens with a different genetic background, i.e., slow-growing hybrids.…”

Innate Immune Responses of Skin Mucosa in Common Carp (Cyprinus Carpio) Fed a Diet Supplemented with Galactooligosaccharides

“…These effects were alleviated by GOS delivered in ovo, most likely due to maintaining intestinal eubiosis [80]. Furthermore, GOS delivered in ovo mitigated harmful effects of chronic heat stress on the performance and welfare of broiler chickens [81], as well as meat composition and quality [82].…”