Effectiveness of using different sources of zinc on the productive performance of laying hens

Heat stress is a major challenge in the poultry industry, adversely affecting birds’ physiological activity, appetite, growth rate, egg production, and egg quality. This study aimed to mitigate the negative effects of high temperatures on laying hen productivity, egg quality, egg zinc content, specific blood parameters, and nutrient utilization during the summer. The experiment involved feeding different zinc sources to laying hens aged 40 to 54 weeks. Eighty Bovans Brown laying hens were randomly assigned to four groups; each had 10 replicates with two hens per replicate. The treatments included a control group (Con), zinc oxide at 500 mg/kg feed (ZnO), zinc carbonate at 500 mg/kg feed (ZnC), and nano-zinc oxide at 50 mg/kg feed (NZn). The zinc experimental treatments resulted in higher egg yield (P < 0.05), egg mass, egg weight, serum zinc levels (P < 0.01), and feed conversion ratio (P < 0.05) compared to the control. When compared to other treatments, nano-zinc oxide produced the lowest AST levels, while zinc carbonate produced the greatest reduction in ALT levels. The zinc oxide group exhibited the greatest serum calcium level. However, no significant impacts were observed in terms of feed intake, nutrient digestibility, egg zinc content, total protein, albumin, globulin, triglycerides, or malondialdehyde. The findings revealed that including zinc carbonate, zinc oxide, and nano-zinc oxide in laying hens’ diets throughout the summer season boosted egg output and egg weight while improving the feed efficiency without compromising the hens’ well-being.