Institute of Animal Science, Guangdong Academy of Agricultural Sciences, Key Laboratory of Animal Nutrition and Feed Science (South China) of Ministry of Agriculture, State Key Laboratory of Livestock and Poultry Breeding, Guangdong Public Laboratory of Animal Breeding and Nutrition, Guangdong Provincial Key Laboratory of Animal Breeding and Nutrition, Guangzhou, 510640, China.
Institute of Animal Science, Guangdong Academy of Agricultural Sciences, Key Laboratory of Animal Nutrition and Feed Science (South China) of Ministry of Agriculture, State Key Laboratory of Livestock and Poultry Breeding, Guangdong Public Laboratory of Animal Breeding and Nutrition, Guangdong Provincial Key Laboratory of Animal Breeding and Nutrition, Guangzhou, 510640, China.
Poult Sci. 2022 Jan;101(1):101539. doi: 10.1016/j.psj.2021.101539. Epub 2021 Oct 13.
This study evaluated dietary Zn supplementation on productive performance, eggshell quality and ultrastructure, and calcium metabolism during eggshell formation in laying ducks. A total of 360 Longyan laying ducks (45-wk) were randomly divided into 5 treatment groups with 6 replicates of 12 birds each and fed for 20 wk. The 6 treatments fed the basal diet supplemented with 0 (control), 20, 40, 80, or 160 mg Zn/kg (ZnSO·HO). Dietary supplemental level at 80 mg/kg increased egg production (4.3%) and mass (5.7%), and decreased FCR (2.9%) compared to the basal diet, and these indices increased quadratically with increasing Zn supplemental levels (P < 0.05). The shell breaking strength (15.8%) and fracture toughness (10.6%) were higher with the supplementation of Zn at 80 mg/kg than the basal diet, and increased quadratically with Zn supplementation (P < 0.05). Dietary supplementation of Zn at 80 mg/kg improved shell ultrastructure by increasing total (9.0%) and effective thickness (14.2%) and decreasing mammillary thickness (12.0%), and their responses were quadratic with increasing Zn levels (P < 0.05). The supplementation of Zn affected the calcium contents in plasma, tibias and ulna, ulna phosphorus content, and linear and quadratic effects were observed, and higher values were observed with 160 mg/kg Zn supplementation than control (P < 0.05). The supplemental Zn level at 80 mg/kg increased shell effective thickness in growth stage (P < 0.05), and shell calcium and phosphorus content in initial and growth stages (P < 0.05). Dietary Zn supplementation did not affect the gene expression of Ca transporters in the eggshell gland, but affected the expression of HCO exchanger in initial and growth stage (P < 0.05). Overall, dietary Zn supplementation could improve productive performance and shell quality in laying ducks at late phase of production, and calcium metabolism and deposition were modulated by Zn influencing HCO secretion and thus affecting shell ultrastructure and quality. A supplemental level of 80 mg/kg Zn in the diet with a basal content of 34.0 mg/kg was optimal, and higher level (160 mg/kg) decreased shell calcium deposition by depressing its metabolism.
本研究评估了在产蛋鸭中，日粮补锌对生产性能、蛋壳质量和超微结构以及蛋壳形成过程中钙代谢的影响。选用 360 只 45 周龄龙岩产蛋鸭，随机分为 5 个处理组，每组 6 个重复，每个重复 12 只鸭，饲养 20 周。6 个处理组分别饲喂基础日粮，基础日粮添加 0（对照组）、20、40、80 或 160 mg/kg（ZnSO·H O）Zn。与基础日粮相比，日粮添加 80 mg/kg Zn 提高了产蛋率（4.3%）和蛋重（5.7%），降低了饲料转化率（2.9%），且这些指标随 Zn 添加水平的增加呈二次增加（P < 0.05）。添加 80 mg/kg Zn 提高了蛋壳的破裂强度（15.8%）和断裂韧性（10.6%），与基础日粮相比，其效果呈二次增加（P < 0.05）。日粮添加 80 mg/kg Zn 通过增加总厚度（9.0%）和有效厚度（14.2%）、降低乳突厚度（12.0%）来改善蛋壳超微结构，且这些响应随 Zn 水平的增加呈二次增加（P < 0.05）。Zn 对血浆、胫骨和尺骨中的钙含量、尺骨磷含量以及线性和二次效应均有影响，与对照组相比，160 mg/kg Zn 组的含量更高（P < 0.05）。日粮添加 80 mg/kg Zn 增加了生长阶段蛋壳的有效厚度（P < 0.05），以及初始和生长阶段蛋壳的钙和磷含量（P < 0.05）。日粮 Zn 补充剂对蛋壳腺中 Ca 转运体的基因表达没有影响，但在初始和生长阶段影响 HCO 交换器的表达（P < 0.05）。总的来说，日粮 Zn 补充剂可以提高产蛋后期产蛋鸭的生产性能和蛋壳质量，通过影响 HCO 的分泌来调节钙代谢和沉积，从而影响蛋壳的超微结构和质量。基础日粮中 Zn 的添加量为 34.0 mg/kg，添加 80 mg/kg Zn 是最佳的，更高的水平（160 mg/kg）通过抑制其代谢来减少蛋壳钙的沉积。
