Effects Of Dietary Fat-soluble Vitamin Deduction Or Excess Feeding On Growth Performance And Rumen Fermentation Of Fattening Sheep

In order to improve the feeding standards of mutton sheep in China,we systematically investigated the effect of partial deduction or excess amount of fat-soluble vitamin A,D,and E on the growth performance,digestibility,slaughter performance,meat quality,rumen fermentation,and microbial nitrogen yield of Dorper × thin-tailed Han crossbred sheep,using the feeding,digestibility,and slaughter trials.The results suggested that a 30% deduction of vitamin E or excess feeding of fat-soluble vitamins reduced the weight gain and nutrient digestibility,and altered the amino acid content in muscle.In addition,excess feeding of fat-soluble vitamins reduced microbial nitrogen yield,which may have negative impacts on production and meat quality of mutton sheep.Experiment 1:Effect of partial deduction or excess amount of fat-soluble vitamin on growth performance,digestion,and metabolism of Dorper × thin-tailed Han crossbred sheepThe purpose of this experiment was to investigate the effect of partial deduction or excess amount of fat-soluble vitamins(A,D,and E)supplementation on growth performance,nutrient apparent digestibility,nitrogen and energy metabolism of Dorper × thin-tailed Han crossbred sheep during fattening period,with an aim to provide theoretical basis for the establishment of fat-soluble vitamin requirements of sheep in China.A total of 120 Dorper × thin-tailed Han crossbred sheep(half male and half female)with average body weight of(26.0±0.51)kg after weaning at 90 days of age were used in the current study.All lambs were randomly divided into 5 groups according to their BW with 24 in each group containing 12 rams and12 ewes each.The sheep in control group(PC group)were fed normal level of fat-soluble vitamins,and30% of vitamin A(PC-VA group),vitamin D(PC-VD group),or vitamin E(PC-VE group)was deducted from PC group in the other three groups,respectively.A high-dose group(PC-7.5 group)was included in which all fat-soluble vitamins were 7.5 times higher than that of the PC group.The experiment lasted for 100 d,with 10 d of adaptation period.Digestibility trial was carried out from 130 days and 160 days.The results showed that during d 150 to 180 days of age,dry matter intake(DMI)and average daily gain(ADG)of the rams in PC-VE group were significantly lower than those in the other groups(P<0.05),and the ADG and feed conversion ratio(FCR)of the ewes in PC-7.5 group was lowest and highest,respectively(P<0.05).Partial deduction of vitamin E and experimental period interactively affected DMI and ADG of rams(P<0.05).Excess amount of fat-soluble vitamins and experimental period interactively affected ADG and FCR of ewes(P<0.05).Excess amount of fat-soluble vitamins and experimental period interactively affected the apparent digestibility of dry matter,organic matter,crude protein and acid detergent fiber(P<0.05),while partial deduction of vitamin E and experimental period interactively affected the apparent digestibility of acid detergent fiber(P<0.05).The results suggested that deduction of 30% of vitamin E or excess amount of fat-soluble vitamins reduced the weight gain and nutrient digestibility of Dorper ×thin-tailed Han crossbred sheep and may negatively affect the performance of sheep.Experiment 2: Effect of partial deduction or excess amount of fat-soluble vitamin supplementation on slaughter performance and meat quality of Dorper × thin-tailed Han crossbred sheepThe purpose of this experiment was to investigate the effect of restriction or excess amount of fat-soluble vitamins(A,D,and E)supplementation on slaughter performance and meat quality of Dorper × thin-tailed Han crossbred fattening lambs,with an aim to evaluate if the recommendation of fat-soluble vitamins provided by NRC is suitable for the sheep production in China.A total of 120 Dorper × thin-tailed Han crossbred sheep(half male and half female)with an average body weight of(26±0.11)kg at 90 d of age were used in the current study.All lambs were randomly divided into 5 groups with 12 rams and 12 ewes in each group.The sheep in control group(PC group)were fed normal level of fat-soluble vitamins,and 30%of vitamin A(PC-VA group),vitamin D(PC-VD group),or vitamin E(PC-VE group)was deducted from PC group in the other three groups,respectively.A high-dose group(PC-7.5 group)was included in which all fat-soluble vitamins were 7.5 times higher than that of the control group.The experiment lasted for 100 d,and the slaughter experiment was carried out at 180 days of age.In terms of slaughter performance,the eye muscle area of PV-7.5 groups was significantly higher than that of PC group(P<0.10);the proportion of TCWS in PC-VA group before slaughter was significantly higher than that of PC-7.5 group.(P<0.05).In terms of meat quality,the color brightness of the PC-7.5 group was significantly lower than that of the other groups(P<0.05),but there was no significant difference between the PC group and the PC group(P>0.05).the C10:0 content in the PC-VA group and the PC-VE group tended to be lower than that in the PC group(P<0.10),and the C20:0 content in the PC-VA group and the PC-VE group.There was a trend lower than the PC-7.5 group(P < 0.10).The content of serine and cystine in PC group were significantly lower than those in other treatment groups(P<0.05).The results suggested that deduction of 30% or excess amount of fat-soluble vitamins intake had no significant impact on slaughter performance and muscle fatty acid content of Dorper × thin-tailed Han crossbred sheep.However,the amino acid content in muscle was affected,which may have potential impacts on meat quality.Experiment 3: Effect of partial deduction or excess amount of fat-soluble vitamin supplementation on rumen fermentation and microbial nitrogen yield of Dorper × thin-tailed Han crossbred sheepThe purpose of this experiment was to investigate the effect of partial deduction or excess amount of fat-soluble vitamins(A,D,or E)supplementation on rumen fermentation parameters,urinary purine derivatives,and microbial nitrogen yield in Dorper × thin-tailed Han crossbred sheep during fattening period,with an aim to evaluate the feeding standard of sheep established by NRC.A total of 120 Dorper ×thin-tailed Han crossbred sheep(half male and half female)with average body weight of(26.0±0.51)kg after weaning at 90 d of age were used in the current study.All lambs were randomly divided into 5 groups according to their BW with 24 in each group containing 12 rams and 12 ewes each.The sheep in control group(PC group)were fed normal level of fat-soluble vitamins,and 30% of vitamin A(PC-VA group),vitamin D(PC-VD group),or vitamin E(PC-VE group)was deducted from PC group in the other three groups,respectively.A high-dose group(PC-7.5 group)was included in which all fat-soluble vitamins were7.5 times higher than that of the control group.The experiment lasted for 100 d,with 10 d of adaptation period.Digestibility trial was carried out during 130 days and 160 days,respectively,and slaughter tests were carried out at 180 days of age.The results showed that the molar ratio of propionate in PC group was significantly higher than that in PC-VA and PC-7.5 groups(P<0.05),and the ratio of acetate/propionate in PC group and PC-VE group was significantly lower than that in PC-VA and PC-7.5 group(P<0.05).The excretion of allantoin and the total purine derivatives in PC-7.5 group of 130-day-old mutton sheep were significantly higher than those in PC group,PC-VA group and PC-VE group(P<0.05).Rumen microbial nitrogen yield was higher in PC-7.5 group than other groups(P<0.05).The excretion of allantoin,the total purine derivatives and the rumen microbial nitrogen yield of 160-day-old mutton sheep were not significant among the treatment groups,but the trends of the three were consistent.There was an interaction between the rumen microbial nitrogen yield and the level of fat-soluble vitamin addition(P<0.05).The results suggested that excess amount of fat-soluble vitamins reduced microbial nitrogen yield in mutton sheep,which may hinder the performance of mutton sheep.