Study On The Mechanism Of High Copper On Preventing Early Weanling Stress Syndrome Of Piglets

An experiment was conducted to examine the effects of high copper diets (fromCuSO₄·5H₂O) on the growth performance, serum antioxidative enzyme activities, serumbiochemical indexes, serum hormone levels and the levels of copper, iron, zinc in sera andtissues of piglets, in order to study the mechanism of high copper on preventing earlyweanling stress syndrome of piglets and security. Sixty "Landrace×Yorkshire×Ding"crossbred weanling piglets (28 d±2 of age) were randomly divided into 3 groups of 20piglets each by weight and sex. The piglets in group â… were fed a basal diet for 28 dpostweaned; the piglets in group II were fed the diets plus 250 mg·kg-1 copper (fromCuSO₄·5H₂O) for 14 d postweaned, then fed a basal diet for additional 14 d; the piglets ingroup III were fed the diets plus 250 mg·kg^-1 copper (from CuSO₄·5H₂O) for 28 dpostweaned. The trial was conducted for 28 d. Body absolute weights (AW), average dailygain (ADG), average day feed intake (ADFI) and The ratio of feed to gain (F/G) of allpiglets were determined on 0,7,14,28 d postweaned, and diarrhea rates were evaluated.Blood samples in thirty (10 per group) of sixty piglets were taken from the anterior venacava on d 0, 7, 14, 28 postweaned for measuring serum CuZn-superoxide dismutase(CuZn-SOD) and ceruloplasmmin (CP) activities; the serum concentrations of total protein(TP), albumin (ALB), globulin (GLOB), cholesterol (CHL), urea nitrogen (UN), alkalinephosphatase(ALP), glutamic-pyruvic transaminase(GPT) and glutamic-oxalacetictransaminase (GOT); the serum contents of growth hormone (GH), insulin (INS),triiodothyronine (T₃) and thyroxin (T₄); and the serum levels of copper, iron and zinc weredetermined at the same time. At the end of the trial, 15 male piglets (5 per group) were bledvia the anterior vena cava. Brain, spleen, kidney, heart, and liver were collected for lateranalysis of trace minerals. The results as follows: 1. The diets adding high copper can significantly improve growth performance ofweanling stress piglets. Compared with the control group, AW of group â…¡ pigletsenhanced respectively by 8.3%(p<0.05),13.2%(p<0.01)and 8.6%(p<0.05)on d 7,14 and 28 postweaned; ADG improved respectively by 58.1%(p<0.01),32.4%(p<0.01)and 13.6%(p<0.01); ADFI improved respectively by 50.2%(p<0.01),15.7%(p<0.01)and 7.7%(p<0.05)on d 0～7,7～14 and 0～28 postweaned; F/G reduced respectively by12.5%(p<0.01) and 4.8%(p<0.05)on d 7～14 and 0～28 postweaned; diarrhea indexreduced by 74.9%(p<0.01) on d 0¹4. Compared with the control group, AW of group â…¢piglets improved by 6.8%(p<0.05),12.8%(p<0.01) and 18.5%(p<0.01) on d 7,14 and 28postweaned; ADG enhanced respectively by 63.7%(p<0.01) , 35.5%(p<0.01) ,26.8%(p<0.01) and 32.3%(p<0.01); ADFI enhanced respectively by 57.7%(p<0.01),15.9%(p<0.01),13.6%(p<0.01) and 17.8%(p<0.01) on d 0～7,7～14,14～28 and 0～28 postweaned; F/G reduced respectively by 14.1%(p<0.01) , 10.4%(p<0.05) and10.6(p<0.01) on d 7～14,14～28 and 0～28 postweaned; diarrhea index reduced73.5%(p<0.01) on d 0¹4 postweaned. Compared with group â…¡, AW of group â…¢ pigletsenhanced by 9.1%(p<0.05) on d 28 postweaned; ADG improved respectively by24.5%(p<0.01) and 16.4%(p<0.01); ADFI improved respectively by 13.1%(p<0.01) and9.4%(p<0.05); F/G reduced respectively by 8.9%(p<0.05) and 6.1%(p<0.05) on d 14～28and 0～28 postweaned; there were no changes between group â…¡ and â…¢ piglets indiarrhea indexes on d 0～14(p>0.05)postweaned. 2. High level supplementation of copper improved significantly serum antioxidativeenzyme activities of weanling stress piglets. Compared with d 0, serum CuZn-SODactivities of the control group decreased by 14.3%(p<0.01) on d 14 postweaned, and therewere no significant changes between d 0 and 28; serum CuZn-SOD activities of group â…¡piglets had no significant change(p>0.05)during the whole experimental period; serumCuZn-SOD activities of group â…¢ piglets had no significant difference from d 0 to 14postweaned(p>0.05), and increased by 12.8%(p<0.05)on d 28 postweaned. Comparedwith the control group, serum...