Response of Feeding Different Levels of Dietary Phosphorus and Supplemental Vitamin D3 on Production Performance, Egg Quality Traits and Serum Biochemical Parameters in Laying Hens

An experiment was conducted to evaluate the effects of dietary available phosphorus (AP) and vitamin D3 on laying hens’ performance, egg quality, and blood biochemical parameters. The 11-week (25-36 weeks) feeding trial involved two levels of AP (0.40 per cent and 0.30 per cent) and three vitamin D3 levels (1600, 2400, and 3200 IU/kg) in a 2×3 factorial design, with fourteen hens in individual cages receiving mash diets ad libitum. Results indicated that a diet with 0.40% AP significantly (P≤0.05) enhanced the feed conversion ratio (FCR) and net feed efficiency compared to 0.30% AP. Significantly (P≤0.01) higher egg production and net efficiency (P≤0.05) were observed at 1600 IU/kg vitamin D3 compared to the other dietary levels of vitamin D3. A dietary combination of 0.40% AP with 2400 IU/ kg vitamin D3 resulted in significantly higher eggshell percentage and ratio, while 0.40% AP with 1600 IU/kg vitamin D3 improved eggshell thickness. Hens on the 0.40% AP diet exhibited significantly better egg weight, eggshell percentage, ratio, thickness, and yolk index than those on the 0.30% AP diet. At 1600 IU/kg vitamin D3, significantly higher yolk index, eggshell percentage, ratio, and thickness were recorded compared to other vitamin D3 levels. Higher alkaline phosphatase activity was noted in hens fed 0.30% AP compared to those fed 0.40% AP. Overall, 0.40% AP combined with 1600 IU/kg vitamin D3 was optimal for enhancing production performance, egg quality traits, and blood biochemical parameters in white leghorn hens from 25 to 36 weeks old. Over the years, the genetic advancement of commercial layer strains has aimed to enhance their productivity. As a result, ongoing research is essential to update the nutritional needs of these birds to achieve their full production capabilities.