Research On Optimized Level Of 25-OH-D₃ And Vitamin D₃ Supplemented To Broilers' Diet

To study the optimized level of 25-OH-D₃ (Hy·D) and Vitamin D₃ supplemented to broilers'diet, a total of 240 male broilers were randomly divided into six treatments, each with four repeats, and each repeat has 10 broilers. The six treatments were as follows: treatment 1 were fed with diet supplemented with Hy·D 0μg/kg and VD₃ 2760 IU/kg, treatment 2 with Hy·D 69μg/kg and VD₃ 0 IU/kg, treatment 3 with Hy·D 34.5μg/kg and VD₃ 1380 IU/kg, treatment 4 with 34.5μg/kg and VD₃ 2760 IU/kg, treatment 5 with Hy·D 69μg/kg and VD₃ 1380 IU/kg, and treatment 6 with 69μg/kg and VD₃ 2760 IU/kg. Criteria including growth performance, nutrients retention, bone quality and, biological and biochemical index of blood were used to evaluate the effects of the six treatments. Feeding and metabolic experiments'results showed that:1. Of the growth performance, there was no significant difference among treatments 1,2,3,4,5 (P>0.05), however, the treatment 6 was significantly slower than the other five groups on average daily weight gain and daily feed intake (P<0.01).2. Of the slaughter index, all the slaughter weight, dressed weight, eviscerated weight with giblet and eviscerated weight of the treatment 6 were significantly lower than other five treatments (P<0.01), but there was no significant difference among the other five treatments (P>0.05). However, on the dressing percentage, percentage of eviscerated with giblet and percentage of eviscerated yield, there showed no obvious differences among all the 6 treatments(P>0.05).3. Of the muscle quality, including water holding capacity, pH value of left brisket muscle (1h after slaughter) and tenderness (shear force value) gave no significant dofference among 6 treatments(p>0.05).4. Of organs'development, there was no significant difference among all 6 treatments (P>0.05) on indicators including weight and index of thymus, bursa, spleen and heart. However, on the liver weight, the treatment 6 was lower than treatments 1, 4 (P<0.05), and significantly lower than treatment 3(P<0.01); and on the index of liver, again the treatment 6 was higher than treatments 1, 3 , 4 (P<0.05), and much higher than treatment 2 and 5(P<0.01). On both the weight and index of liver, no significant differences were found among treatments 1, 2, 3, 4, and 5 (Pï¹¥0.05).5. Of biological and biochemical index of blood, no differences were found on the phosphorus and calcium in the serum, AKP, T-AOC, SOD, CAT, MDA(P>0.05).6. Of nutrients retention, on the energy deposition, dry matter metabolic rate, organic matter metabolic rate, nitrogen deposition, and phosphorus deposition rate, only treatment 6 was significantly lower than other five treatments(P<0.01). On the calcium deposition rate, treat 6 was also lower than treat 4(P<0.05), and quite lower than treatment 1, 2, 3 and 5 (P<0.01). However, among the other five treatments there was no significant difference (P>0.05) on all these indicators.Based on above results, supplementation of Hy·D at 34.5 ug/kg and VD₃ at 1380 IU/kg to diet was best, but Hy·D at 69 ug/kg and VD₃ at 2760 IU/kg negatively affected the growth performance of broilers.