Effects of environmental temperature and dietary manganese on egg production performance, egg quality, and some plasma biochemical traits of broiler breeders1

Abstract

An experiment was conducted to investigate the effects of environmental temperature and dietary Mn on egg production performance, egg quality, and some plasma biochemical traits of broiler breeders. A completely randomized factorial design involved 2 environmental temperatures (a normal temperature, 21 ± 1°C, and a high temperature, 32 ± 1°C) × 3 dietary Mn treatments (a Mn-unsupplemented corn–soybean meal basal diet or the basal diet supplemented with 120 mg of Mn/kg of diet as either MnSO4·H2O or manganese proteinate). There were 6 treatments with 6 replicates (4 birds per replicate). High temperature decreased egg weight (P < 0.0001), laying rate (P < 0.0001), egg yield (P < 0.0001), feed intake (P < 0.0001), egg:feed ratio (P < 0.0001), eggshell strength (P < 0.05) and thickness (P < 0.0001), plasma triiodothyronine level (P < 0.05), and alkaline phosphatase activity (P < 0.04) whereas it increased rectal temperature (P < 0.0001); plasma malondialdehyde level (P < 0.02); and activities (P < 0.002) of lactic dehydrogenase, aspartate aminotransferase, and creatine kinase. Broiler breeders fed the diets supplemented with Mn regardless of source had greater (P < 0.05) eggshell strength and lower (P ≤ 0.05) plasma triiodothyronine level and protein carbonyl content than those fed the control diet. The broiler breeders fed the diet supplemented with the organic Mn had greater (P < 0.01) eggshell thickness than those fed the control diet. There were interactions (P < 0.05) between environmental temperature and dietary Mn in laying rate, egg yield, feed intake, and egg:feed ratio. Under normal temperature, dietary Mn did not affect the above 4 parameters; however, under high temperature, broiler breeders fed the diet supplemented with the organic Mn showed greater (P < 0.03) improvements in these 4 parameters than those fed the control diet. The results from this study indicated that high temperature significantly impaired egg production performance and eggshell quality and induced lipid peroxidation and tissue damage whereas dietary supplementation of either organic or inorganic Mn improved eggshell strength and thermotolerance and reduced protein oxidation and that the organic Mn could alleviate the negative effect of high temperature on egg production performance of broiler breeders at the period of 32 to 45 wk of age.

Effect of dietary manganese on antioxidant status and expression levels of heat-shock proteins and factors in tissues of laying broiler breeders under normal and high environmental temperatures

“…Heat stress is believed to produce ROS and induce oxidative damage in broilers (31,32) and laying hens (6) . In the current study, HT showed a clear trend towards elevating breast muscle MDA content and the increased plasma MDA level was also observed in our another study (17) , suggesting that lipid peroxidation occurs under the HT condition. However, at the same time, HT led to an increase in MnSOD activity in breast muscle.…”

“…Relative moisture in the two rooms was kept at 40 (SEM 5) % during the experimental period of 14 weeks (32-45 weeks of age). Our previous results (17) on rectal temperature indicated that all of the laying broiler breeders under HT were in a heat stress status throughout the experimental period. The daily feed intake of birds in each replicate was recorded and reported previously (17) .…”

“…Our previous results (17) on rectal temperature indicated that all of the laying broiler breeders under HT were in a heat stress status throughout the experimental period. The daily feed intake of birds in each replicate was recorded and reported previously (17) . All broiler breeders from both NT and HT were feedrestricted with the same amount of the treatment diets each day from 32 to 35 weeks of age.…”

“…The managements of broiler breeders and dietary treatments for this experiment were the same as described previously (17) . Briefly, 144 18-week-old female broiler breeders (Arbor Acres; Huadu Broiler Company) were randomly allotted to one of six treatments with six replicates (four birds per replicate) for each treatment based upon body weight.…”

“…Our recent results have shown that high environmental temperature significantly impaired egg production performance and eggshell quality and induced lipid peroxidation and tissue damage, whereas dietary supplementation of either organic or inorganic Mn improved eggshell strength and thermotolerance and reduced protein oxidation, and that the organic Mn with the moderate chelation strength could alleviate the negative effect of high temperature on egg production performance of broiler breeders at the period of 32-45 weeks of age (17) . However, it is not clear whether dietary supplementation with Mn, especially organic Mn with moderate chelation strength, can reduce oxidative damage and increase heat stress resistance with the enhancements of antioxidant ability in broiler breeders.…”