Effects Of Different Levels Of Dietary Tea Powder On Growth Performance,Meat Quality,and Serum Biochemical Indices Of Pigs

With the continuous improvement of the living standards of our residents,the demand for meat products is changing from "satisfying quantity" to "focusing on quality".In the process of animal husbandry,in addition to improving animal production performance,improving meat quality and nutrition level is also one of the important goals,which also affects and determines consumer purchase decisions to a certain extent.At the same time,due to the shortage of traditional feed materials,the phenomenon of "human and animal competition for grain" has become more serious.A large number of studies have proved that various functional substances in tea(tea polyphenols,tea polysaccharides,and various amino acids,etc.)can help promote animal growth,improve the body’s antioxidant level and meat quality.Based on this,this study takes the development of tea processing by-products as an unconventional feed resource as a starting point,and explores the effects of adding different proportions of tea powder to pig diets on pig growth performance,meat quality,and serum biochemical indicators.In the first experiment(digestion test),12 healthy pigs with an average body weight of 20 ± 2 kg were selected and randomly divided into 2 groups(n = 6).The control group was fed a full-price basic diet,and the test group was fed a test diet containing 20% tea powder.Using the digestion test method,combining with the nutritional composition and level of tea powder,the apparent digestibility of pigs to tea powder is calculated.The results showed that the total energy of tea powder(GE),crude protein(CP),crude fat(EE),crude fiber(CF),calcium(Ca)and phosphorus(P)were 14.01 MJ/kg,23.5%,3.91%,10.74%,0.79%,0.58%;the apparent digestibility of pigs to the above nutrients is 73.56%,80.11%,34.91%,40.35%,74.23%,35.76%;the digestible nutrients are 10.31MJ/kg,18.82%,1.36%,4.33%,0.59%,0.21%.In the second experiment(feeding experiment),120 healthy pigs were selected,and the average initial weight was 20 ± 2 kg.They were randomly divided into 5groups(n = 24)according to the principle of similar body weight.4 pigs.Different experimental groups were fed with basic diets or 1%,2%,4%,6% tea powder full-price diets for 60 days.After the feeding,10 pigs from each group were randomly selected for slaughter,and their production performance,carcass traits,meat quality,muscle nutrients,serum biochemical indicators,antioxidant levels and other indicators were determined.The results show that:(1)Production performance and meat quality: the addition of different levels of tea powder in the diet does not affect the growth performance of the pig(P > 0.05),and the addition of 6% could significantly reduced the average daily intake(ADFI)(P < 0.05);on the premise of not affecting the slaughter rate(P > 0.05),adding tea powder could help reduced the back fat thickness,oil weight and fat rate(P < 0.05),and increased the lean meat rate(P < 0.05);the addition of tea powder has no significant effect on the content of intramuscular fat(IMF)(P > 0.05),but it could significantly increased muscle protein levels(P < 0.05);(2)muscle nutritional ingredients: the addition of tea powder could significantly improved muscle total amino acids(TAA)and total essential amino acids(EAA)(P < 0.05),but had no significant effect on the content of total flavored amino acids(FAA)(P > 0.05).At the same time,there was no significant difference in the total amount of muscle saturated fatty acid(SFA),monounsaturated fatty acid(MUFA),and polyunsaturated fatty acid(PUFA)(P > 0.05),but the content of C20:5n3 was significantly improved(P<0.05);(3)Blood biochemical indicators and antioxidant levels: adding tea powder could significantly increased the content of aspartate aminotransferase(AST),alanine aminotransferase(ALT),high-density lipoprotein(HDL),lipase(LIPC)(P < 0.05),and reduce the content of low-density lipoprotein(LDL)(P < 0.05),while serum glutathione peroxidase(GSH-Px)activity was significantly increased(P < 0.05),total antioxidant capacity(TAO-C)and oxide dismutase(SOD)were improved to some extent.In summary,the addition of different levels of tea powder in the diet can help improve the carcass traits and meat quality of pigs,and improve the body’s antioxidant capacity,and the optimal amount of tea powder is 4%.