| Ewes dietary nutrition imbalance could result in reproduction reduction,lamb growth slowly and immnuity reduction,death rate increase,which could not be remited by increasing nutrition levels at lambs rest of life.Hence,the study was conducted to investigate the effects of chromium(Cr III)supplementation during ewe late lactation on growth performance,immunity and oxidation resistance of offspring lambs.The study composited by two parts described as below:Experiment 1: Effects of Chromium Propionate(CrPro)supplementation during late lactation period on serum biochemistry profiles and milk composition of ewesAfter 7 days preparation,a total of 40 ewes(second or third parity)at 90 d of pregnancy(90±3.53d)were selected to assigned to one of four treatments(control,CrPro 0.4,CrPro 1.2,CrPro 2.0 mg Cr/kg)according to bodyweight(52.36±8.24 kg),resulting in 4 treatments with 10 replicate per pen.The feed intake was record daily.The serum samples were collected at 120 d of pregnancy to measure the effects of Cr supplementation on serum nutrition metabolism profiles,oxidation resistance,reproduction hormones concentrations and immunoglobulin concentrations of ewes.Milk samples were collected at the day of partus(0d),3d,7d,14 d,21d,and stored with a little preservative to determine the effects of Cr supplementation on milk composition.5 mL milk samples of 0d were collected to measure the effects of Cr supplementation on immunoglobulin concentrations of ewes.The results were showed as below:(1)Ewes DMI were not affected by Cr supplementation during 90 d of pregnancy to partus period(P = 0.2540)and during 0-21 d of post-partus(P = 0.9512);(2)Serum SOD(P = 0.3358)and GSH-PX(P = 0.8101)activities were not affected by Cr supplementation.However,serum MDA concentration was linear increased by Cr supplementation(P = 0.0076);(3)There was no difference in serum GLU(P = 0.4268)and SUN(P = 0.9499)concentration between different Cr supplementation groups.Serum TP concentration was linear increased by Cr supplementation(P = 0.0009);(4)Cr supplementation had a quadratic tendency to increase ewe serum FSH concentration(P = 0.0504),and the 0.4 mg/kg group was the highest.Serum P4(P = 0.0131)content was linear increased by Cr supplementation.However,LH(P = 0.4271)and E2(P = 0.4940)concentrations were not affected by Cr supplementation;(5)The concentration of serum IgA was not affected by different level of Cr supplementation on ewe at 120 d pregnancy(P = 0.7545).Serum IgG(P = 0.0113)and IgM(P = 0.0015)concentrations were linear increased by Cr supplementation on 120 d pregnancy ewe;(6)No difference was observed in milk fat(P = 0.1023),skim solids(P = 0.7156),lactoprotein(P = 0.5954),lactose(P = 0.7538)and ash(P = 0.6325)contents during the 0-21 d post-partus.Milk fat percentage of 0d(P = 0.0058)and 3d(P = 0.0080)were linear increased by Cr supplementation;(7)Milk IgA(P = 0.0049),IgG(P = 0.0081)and IgM(P = 0.0033)concentrations were linear increased by Cr supplementation at the day of partus;(8)Umbilical cord(P = 0.0012)and colostrums(P< 0.0001)Cr depositions were linear increased by Cr supplementation.Experiment 2: Effects of maternal Cr supplementation during late lactation on growth performance,oxidation resistance and immunity of offspring lambsThe fetus amounts,birth weight,stillbirth,mummies were recorded at the day of partus.The lambs were fed by their own mother until the 21 d old under the condition of that lambs could get enough milk from their own mother.At 21 d old,the male lambs were selected from each litter by average body weight.The selected male lambs were injected by LPS(Lipopolysaccharide),and were slaughtered at 2 h after injection.21 d weight was recorded to calculate the growth performance during 0-21 d.The serum samples were collected to calculate the effects of maternal Cr supplementation on serum immunoglobulin concentrations and oxidation resistance of 21 d old lambs.The liver samples were collected to calculate the effects of maternal Cr supplementation on liver oxidation resistance of 21 d old lambs.The small intestinal samples were collected to measure effects of maternal Cr supplementation on small intestinal immunity of 21 d old lambs.The results were showed as below:(1)The average birth weight(P = 0.6539)and litter weight(P = 0.9240)of offspring lambs were not affected by maternal Cr supplementation;(2)The average weight(P = 0.5150)and litter weight(P = 0.9096)of 21 day-old offspring lambs were not affected by maternal Cr supplementation,and the average daily gain(ADG)(P = 0.1954)was also not affected by maternal Cr supplementation during the 0-21d;(3)Kidney index(P = 0.0114)of 21 d old lambs was linear increased by maternal Cr supplementation.Thymus index(P = 0.0140)and rumen index(P = 0.0254)of 21 d old lambs were quadratic increased by maternal Cr supplementation,and 1.2 mg/kg group was the highest at thymus and rumen indexes.No difference was found in heart(P = 0.9421),liver(P = 0.3064),spleen(P = 0.9718),lung(P = 0.4857),reticulum(P = 0.7535),omasum(P = 0.4291),and abomasums(P = 0.2429)indexes of 21 d old lambs between different maternal Cr supplementation groups;(4)Serum SOD activity of 21 d old lambs was quadratic increased(P = 0.0035)by maternal Cr supplementation,and the highest was 1.2 mg/kg supplementation.MDA concentration of 21 d old lambs was linear decreased(P = 0.0365)and GSH-PX activity of 21 d old lambs was linear increased(P = 0.0033)by maternal Cr supplementation.However,the 21 d old lamb SUN concentration was not affected by maternal Cr supplementation(P = 0.2111);(5)The 21 d old lamb serum IgG(P = 0.0081)and IgM(P = 0.0120)concentrations were affected by maternal Cr supplementation.Serum IgG(P = 0.0137)concentration was quadratic increased with the maternal Cr supplementation increasing,and the 0.4 mg/kg was the highest However,21 d old lamb serum IgA(P = 0.1207)concentration was not affected by maternal Cr supplementation;(6)The 21 d old lamb liver SOD activity(P = 0.8718),MDA concentration(P = 0.7898)and GSH-PX activity(P = 0.3471)were not affected by maternal Cr supplementation;(7)Maternal Cr supplementation had a tendency to reduce ileum intestine wall thickness(P = 0.0861).The villus height(VH)(P = 0.0052)and villus height: crypt depth(VH/CD)(P = 0.0186)of duodenum,intestinal wall thickness(P = 0.0249)of jejunum of 21 d old lamb were quadratic increased by maternal Cr supplementation,and the 1.2,1.2 and 0.4 mg/kg were the highest respectively.Crypt depth(CD)of ileum of 21 d old lamb(P = 0.0073)were linear decreased by maternal Cr supplementation.No difference was observed in CD(P = 0.7629)and intestinal wall thickness(P = 0.9853)of duodenum,VH(P = 0.9661),CD(P = 0.5452)and VH/CD(P = 0.2841)of jejunum,and VH(P = 0.9661)and VH/CD(P = 0.1848)of ileum of 21 d old lambs suffered from maternal Cr supplementation;(8)No difference was observed in mucosal alkaline phosphatase(AKP)(P = 0.4144)and diamine oxidase(DAO)(P = 0.3530)activities,interleukin-1?(IL-1?)(P = 0.5247),interleukin-6(IL-6)(P = 0.2529),interleukin-10(IL-10)(P = 0.2430)and sencretory immunoglobulin A(sIgA)(P = 0.2223)concentrations of jejunum of 21 d old lambs suffered from maternal Cr supplementation;(9)Cr concentration of lambs liver was linear increased by maternal Cr supplementation(P = 0.0073).It can be indicated from the study that CrPro supplementation could improve ewe immunity and reproduction,increase colostrums immunoglobulin concentrations,improve lambs small intestinal development,enhance lambs immunity and oxidation resistance,and 0.4 mg/kg maternal Cr supplementation was the best for offspring lambs immunity.The study offered some scientific basis to Cr supplementation onruminant nutritional metabolism. |
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