饲喂水平对冬毛生长期雄性北极狐生产性能、器官发育及机体能量沉积的影响

旨在研究不同饲喂水平对冬毛生长期雄性北极狐生产性能、器官发育及机体能量沉积的影响。本试验选取46只161日龄，平均体重为（7 285±5.77）g健康的雄性北极狐，其中6只北极狐作为试验初屠宰试验对照，另外40只北极狐随机分成4组（每组10个重复，每个重复1只），分别按照自由采食组（AL，I组）、自由采食量的80%组（IR80，II组）、自由采食量的60%组（IR60，III组）和自由采食量的40%组（IR40，IV组）4个水平饲喂，预饲期7 d，试验期67 d，通过饲养试验、屠宰试验并结合化学分析方法来评定生长性能、毛皮品质、器官发育及机体能量沉积的各项指标。结果表明：1）随饲喂水平降低，平均干物质采食量（ADFI）呈极显著降低（P<0.01），II组平均日增重（ADG）极显著高于IV组（P<0.01），显著高于III组（P<0.05），与I组差异不显著（P>0.05）；饲喂水平对北极狐末重和料重比（F/G）无显著影响（P>0.05），但II组末重略高于其他组，F/G略低于其他组。2）饲喂水平极显著影响了北极狐鲜皮长（P<0.01），I组极显著高于III和IV组，与II组无显著差异（P>0.05）；随饲喂水平降低，体长、干皮长、针毛长和绒毛长均呈降低趋势，但各组间均无显著性差异（P>0.05）。3）饲喂水平显著影响了北极狐心脏重和心脏指数（P<0.05或P<0.01），II组心脏重显著高于III组（P<0.05），与I组和IV组差异不显著（P>0.05），IV组心脏指数极显著高于I组（P<0.01），显著高于III组（P<0.05），与II组差异不显著（P>0.05），而饲喂水平对肝、肾、肺和脾重及其脏器指数均无显著影响（P>0.05）。4）随饲喂水平降低，毛皮增重、毛皮脂肪沉积及其能量沉积、毛皮沉积总能量、胴体脂肪沉积及其能量沉积、胴体蛋白沉积及其能量沉积和胴体沉积总能量均呈降低趋势，但饲喂水平对毛皮、胴体能量沉积各项指标均无显著性影响（P>0.05）。采用适当限饲（IR80）不影响冬毛生长期北极狐机体器官的正常发育，能够保证其体重增长及毛皮品质，提高了饲料转化效率，且还降低了机体能量沉积过度带来的肥胖风险。

Effects of Feeding Level on Productive Performance,Organ Development and Body Energy Deposition of Male Arctic Foxes during the Winter Fur Growth Period

This experiment was conducted to study the effect of feeding level on productive performance, organ development and body energy deposition of male Arctic foxes during the winter fur growth period. Forty-six healthy 161-day-old male Arctic foxes with average body weight of (7 285±5.77) g were selected, including 6 Arctic foxes as slaughter trial control at the beginning of the trial, another 40 Arctic foxes were randomly divided into 4 groups with 10 replicates per group and 1 fox per replicate. The foxes were offered diet for ad libitum (AL,Group I), 80% (IR80,Group II), 60% (IR60,Group III) and 40% (IR40,Group IV) of ad libitum intake, respectively. The experiment was 7 days for adaption and 67 days for trial period. The parameters of growth performance, fur quality, organ development and body energy deposition were evaluated by means of feeding, slaughter trials and chemical analysis methods. The results showed as follows:1) With the decrease of feeding level, ADFI showed an extremely significant decrease(P<0.01), ADG in group II was extremely significantly higher than that in group IV (P<0.01), and significantly higher than that in group III (P<0.05), and there was no significant difference between group II and I (P>0.05). Final weight (FW) and F/G were not significantly different among different groups(P>0.05), whereas the FW in group II were higher than those in the other groups, and F/G in group II were lower than those in the other groups. 2) Different feeding levels extremely significantly affected length of fresh pelt (P<0.01). Length of fresh pelt in group I was extremely significantly higher than those in group III and IV (P<0.01), and no significant difference was found between group I and II (P>0.05). With the decrease of feeding level, there were decreased trends in body length, length of dried pelt, length of guard hair and length of under hair, but there were no significant difference among 4 groups (P>0.05). 3) Different feeding levels significantly affected heart weight and heart index (P<0.05 or P<0.01). Heart weight in group II was significantly higher than that in group III (P<0.05), and no significant difference was found among group I, II and IV (P>0.05). Heart index in group IV was extremely significantly higher than that in group I (P<0.01), and significantly higher than that in group III (P<0.05), but no significant difference was found between group II and IV (P>0.05).Whereas feeding levels did not significantly affect the weight and indexes of liver, kidney, spleen, lung (P>0.05). 4)With the decrease of feeding level, there were all decreased trends in pelt weight gain, pelt fat deposition and its energy deposition, total pelt energy deposition, carcass fat deposition and its energy deposition, carcass protein deposition and its energy deposition as well as total carcass energy deposition, whereas there were no significant difference in all parameters of energy deposition of pelt and carcass among different groups(P>0.05). Feeding 80% of ad libitum intake (IR 80) does not affect the normal development of body organs, could ensure the body weight gain and fur quality, improve the feed efficiency and also reduce the obesity risk due to excessive energy deposition of Arctic foxes during the winter fur growth period.