Different dietary electrolyte balance values on performance, egg, and bone quality of Japanese quail (Coturnix Coturnix Japonica) under heat stress.

The objective of this study was to evaluate the productive performance and quality of eggs and bones of Japanese quails that received different dietary electrolyte balance (EB) and were submitted to thermoneutrality or heat stress conditions. Eight hundred Japanese quails of 21 days of age were selected and distributed randomly in two bioclimatic chambers: thermoneutral chamber (23 °C ± 2 °C) and heat-stress chamber (33 °C ± 2 °C). The treatments were in a 2 × 5 factorial arrangement, with two temperatures and five EB levels (165, 215, 265, 315, 365 mEq/kg) with four replicates of 20 birds each. The productive performance and egg quality (in 3 cycles of 21 days) were measured. At 105 days old, the bone quality was evaluated. Data were analyzed by Minitab, and the means were compared by Tukey's test and regression test for levels (P < 0.05). Quails submitted to thermoneutrality showed better performance and egg and bone quality. The highest production rate was the EB level of 265 mEq/kg. Low values of EB (165 and 215 mEq/kg) and high values (365) impaired egg quality, and the ideal was 315 mEq/kg. Lower levels of balance provided poor bone density. In conclusion, the results of this study indicated that heat stress impairs the production and quality of quail eggs and bones. Furthermore, by using intermediate EB levels (265 and 315) mEq/kg, it is possible to improve egg production and egg quality, and using high levels increases bone mineral density.

Effects of feeding spray-dried plasma to broiler breeders and their progeny on broiler performance under stressful rearing conditions of coccidial challenge and heat stress.

A total of 216 Cobb 500 broiler breeder hens were randomly distributed across 2 dietary treatments with 0 or 1% spray-dried plasma (SDP) resulting in 27 replications/treatment and 4 birds/replication. In addition, 36 roosters were divided between the same treatments and housed, in individual pens, being each bird considered a replicate. Experimental diets were fed from 26 wk until 65 wk of age. At 29, 45, and 63 wk of age, broiler breeder hens were inseminated, and eggs were incubated. Three progeny studies were performed and hatched birds were allocated in a randomized 2 × 2 factorial design (maternal diet: with or without inclusion of 1% SDP × progeny diet: with or without the inclusion of 2% SDP from 1 to 7 d of age). After 7 d of age, all birds received the same diet until 42 d. In all trials, birds were challenged with coccidiosis vaccine at 7 d of age. Furthermore, in the second experiment, heat stress was also included for 6 h a day during the whole trial. At 42-days posthatch in the first experiment, greater FI, BW, and BWG in chicks hatched from breeders fed 1% dietary SDP was observed. This effect did not extend to the other hatches. In the second trial, a decreased FCR in broilers fed the control diet from breeder hens fed 1 % of SDP was observed, as well as an interaction between the SDP groups, since broilers supplemented with SDP and originated from breeders fed SDP showed higher BW and BWG in comparison to other groups at 42 d. In the third trial, contrary to what was observed in the first study, SDP supplementation did not affect any of the performance indexes. In the 3 studies, no differences were found in carcass characteristics. SDP did not affect hen BW, egg production, fertility, or hatch of fertile. These results suggest that providing dietary SDP to broilers has some beneficial effects on broiler chickens.

Pequi Oil (Caryocar brasiliense Camb.) Attenuates the Adverse Effects of Cyclical Heat Stress and Modulates the Oxidative Stress-Related Genes in Broiler Chickens.

The present study was conducted to determine the possible antioxidant protection of pequi oil (PO) against cyclic heat stress in broiler chickens and to highlight the application of PO as a promising additive in broiler feed. A total of 400 one-day-old male broiler chicks (Cobb 500) were randomly assigned to 2 × 5 factorially arranged treatments: two temperature-controlled rooms (thermoneutral-TN or heat stress-HS for 8 h/day) and five dietary PO levels (0, 1.5, 3.0, 4.5, or 6.0 g/kg diet) for 42 days. Each treatment consisted of eight replicates of five birds. The results showed that HS increased glucose (p = 0.006), triglycerides (p < 0.001), and HDL (p = 0.042) at 21 days and reduced (p = 0.005) serum total cholesterol at 42 days. The results also showed that HS increased the contents of alanine aminotransferase (ALT) and aspartate aminotransferase (AST). In contrast, PO linearly decreased AST (p = 0.048) and ALT (p = 0.020) at 21 and 42 days, respectively. The heterophil-to-lymphocyte ratio in the birds under HS was higher than in those in the TN environment (p = 0.046). Heat stress decreased (p = 0.032) the relative weight of their livers at 21 days. The superoxide dismutase activity increased (p = 0.010) in the HS treatments in comparison to the TN treatments, while the glutathione peroxidase activity in the liver decreased (p < 0.001) at 42 days; however, the activity of catalase had no significant effects. Meanwhile, increasing the dietary PO levels linearly decreased plasma malondialdehyde (p < 0.001) in the birds in the HS environment. In addition, PO reduced (p = 0.027) the expression of Hsp 70 in the liver by 92% when compared to the TN treatment without PO, mainly at the 6.0 g/kg diet level. The expression of Nrf2 was upregulated by 37% (p = 0.049) in response to PO with the 6.0 g/kg diet compared to the HS treatment without PO. In conclusion, PO supplementation alleviated the adverse effects of HS on broilers due to its antioxidant action and modulation of the genes related to oxidative stress, providing insights into its application as a potential feed additive in broiler production.