Studies On Growing Matabolism And Fasting Metabolism In Song Liao Hei Pigs At Different Live Weight Groups

By means of open-circuit respiratory apparatus,six purebred Song Liao Hei barrow,w hich were divded into three live weight groups(20kg,40kg,60kg),were used on the experiment for measuring their gas exchange,heat production,urin nitrogen excretion,body protein and fat retain in the fasting period and growing period,Digestibility of the different nutri ents in different live weight classes and retained Nitrogen and Carbon was calculated.Requ irement of metabolizable energy for maintenance was estimated according to the fasting heat production.Fasting time is 48 hours.The oxygen consumption of pigs at different live weight groups is 2.70±3.461,38.92±2.59,34.85±2.49L/kg^0.75.The oxygen consumption in the first priod is higher than that in the second,third.(P＞0.05) The variant trend of carbon dioxide production at different live weight groups is similar to that of oxygen consumption.The carbon dioxide production in three period is 2.24±2.80,39.723±2.87,38.02±2.79L/kg^0.75.The respiration quotients at different live weight groups have no significant.The respiration quotient changes between0.9 9and1.09.The first period is higher than that in the seco-nd and third,Difference between the first period and the rest period is significant.(P＜0.05)).The sec-ond period is higher than that in the third,Difference between the second and the third period is not significant. (P＞0.05).The respiration quotient increases with increasing live weight.The digestibility of the Song Liao Hei barrow to crude protein decreases with increasing live weight.the difference is not significant.The digestibility of crude fat decreases with increasing live weight.the difference between the first period and the rest period is significant.the difference between the second one and the third o-ne is not significant.The digestibility of crude fibre and free extract nitrogen decreases with increaseing live weight.The intaken nitrogen and retained nitrogen is increased with increasing live weight.The coefficie-nt of RN/DN is stable in different live weight class.The retained carbon and deposited fat is incre-ased with increasing live weight.The difference between three live weight class is significant. The oxygen consumption of pigs at different live weight groups at fasting period is increased w-ith increasing live weight.The oxygen consumption in the first priod is highe r than that in the second,third.(P＞0.05) The variant trend of carbon dioxide production at different live weight groups is similar to that of oxygen consumption.The respiration quotients at different live weight groups have no significant.quotient changes between0.70 9and 0.8.The nitrogen in urine and heat production is increased with increasing live weight class.But the coefficient of HP/kg^0.75 decreased with increasing live weight.The first period is higher than that in the second and third,Difference between the first period and the rest period is significant.(P＜0.05).The second period is higher than that in the third, Difference between the second and the third period is not significant.(P＞0.05).The the coefficient of HP/kg^0.75are 616.55,455.62,419.01.therefore the function of estimating ME m in three live weightclass is 616.55W^0.75,455.62W^0.75,419.39W^0.75 KJ/kg^0.75d.