杂粮杂粕和低蛋白质杂粮杂粕饲粮对后备公猪生长性能、营养物质表观消化率和睾丸发育的影响OA

This experiment was conducted to investigate the effects of replacing corn-soybean meal diet with miscellaneous grain and meal diets(including wheat,barley,sorghum,brown rice,cottonseed meal,rapeseed meal,linseed cake,and corn DDGS)with normal or low-protein on growth performance,nutrient apparent di-gestibility,and testicular development of replacement boars.Twenty-seven 65-day-old three-way crossbred boars with an initial body weight of(17.76±1.28)kg were randomly assigned to 3 groups with 9 replicates per group.Boars in the control group(CON group)were fed a basal corn-soybean meal diet,those in the miscel-laneous grain and meal group(UD group)were fed a miscellaneous grain and meal diet with the same crude protein level as the CON group,and those in the low-protein miscellaneous grain and meal group(LUD group)were fed a miscellaneous grain and meal diet with crude protein level reduced by 2 percentage points.The experiment lasted for 55 days,including an early phase(days 1 to 12),a middle phase(days 13 to 34),and a late phase(days 35 to 55).The results showed as follows:1)during the early phase,the feed-to-gain ratio(F/G)of replacement boars in the UD group was significantly lower than that in the CON and LUD groups(P＜0.05).However,during the middle,late,and overall phases,no significant differences were ob-served in average daily gain(ADG),average daily feed intake(ADFI),and F/G among the UD,CON,and LUD groups(P＞0.05).2)Compared with the CON group,during the middle phase,the UD group had sig-nificantly or extremely significantly lower apparent digestibility of crude protein,dry matter,and gross energy(P＜0.05 or P＜0.01),but significantly higher apparent digestibility of ether extract(P＜0.05).During the late phase,only the apparent digestibility of gross energy in the UD group was significantly lower than that in the CON group(P＜0.05).Compared with the UD group,during the middle phase,all nutrient apparent digesti-bility in the LUD group were significantly or extremely significantly decreased(P＜0.05 or P＜0.01);during the late phase,except for the apparent digestibility of ether extract and gross energy,all other nutrient apparent digestibility in the LUD group were significantly or extremely significantly decreased(P＜0.05 or P＜0.01).3)Compared with the UD group,the serum urea nitrogen(UN)content of replacement boars in the LUD group was significantly decreased(P＜0.05).4)No significant differences were found in testicular volume,weight,testicular index,or the numbers of spermatogonia and Sertoli cells per seminiferous tubule among the UD,CON,and LUD groups(P＞0.05).5)The serum luteinizing hormone(LH)content of replacement boars in the UD group was significantly higher than that in the CON group(P＜0.05),while the testicular tissue folli-cle-stimulating hormone(FSH)content in the LUD group was significantly lower than that in the UD group(P＜0.05).6)The relative expression level of the testosterone synthesis-related gene cytochrome P450 11A1(P450scc)in testicular tissue of the LUD group was significantly higher than that of the UD group(P＜0.05).In summary,under the conditions of this experiment,feeding miscellaneous grain and meal diets with normal or low-protein does not affect the growth performance and testicular development of replacement boars;al-though the apparent digestibility of dry matter,crude protein,and gross energy decreases,while the apparent digestibility of ether extract increases.Additionally,feeding the miscellaneous grain and meal diet decreases se-rum LH content,while feeding the low-protein miscellaneous grain and meal diet decreases testicular FSH con-tent and tends to upregulate the expression of genes related to testosterone synthesis.[Chinese Journal of Ani-mal Nutrition,2026,38(5):3333-3348]