THE EFFECT OF DIFFERENT AMOUNT OF WATER INTAKE ON THE LEVEL OF BLOOD GLUCOSE,LACTIC ACID,FFA AND THE AMOUNT OF URINARY NITROGEN IN PIG

Zhou Dacheng Qi Shunzhang Zhang Huanrong Niou Wenbiao Zeng Bing ji

This trial was carried out during 1963—1964 which was a part of our research on the effect of different amount of water intake on the the digestion and metabolism in pig.In the beginning,16 castrated young boars of Jilin-Black breed similar in birth date and birth wei- ght were used for a prefeeding test.During the pre-feeding test per- iod, the animals were 4—8 months of age,kept under similar condi- tions and the levels of their blood glucose,lactic acid,FFA and urinary nitrogen were tested.After this period,6 pigs were selected out and divided evenly into two groups similar in blood glucose,lactic acid,FFA and urinary nitrogen levels in order to minimize the effect of individual difference. Two groups of pigs(from 8months of age)were then kept in the same conditions including the quality and quantity of feed ingested but the amount of water intake of one group(high water group)was twice as much as that of the other group(low water group).The ef- fect of different amounts of water intake was then compared. At the age of 8—12 months,the levels of blood glucose,lactic acid and FFA of the animals were analyzed 8 times and the amount of urinary nitrogen was analyzed 4 times.The fast test was carried out at the age of 13 months. 1.Under our experimental conditions,the increase in water intake might increase the levels of blood glucose and lactic acid and decrease the level of plasma FFA,but had no influence on amount of urinary nitrogen.These suggest that the regulatory function of pigs may be changed by ingesting more water so that it can maintain their blood glucose in a higher level which in turn promotes the utilization of glucose and inhibits the mobilization of fatty acid while the cataboli- sm of protion is not influenced significantly. 2.During the period of fasting,the change in metabolism of these 2 groups showed the same tendency.That is,after the beginning of fasting,the levels of blood glucose and lactic acid and the amount of urinary nitrogen in both groups tended to decrease while the level of plasma FFA tended to increase.And at about 36 hours after the last feeding,the levels of blood glucose and lactic acid and the amount of urinary nitrogen all dropped to their minimum values and then went up while the level of plasma FFA reached its maximum value and then started to drop.All this suggests that at about 36 hours after feeding there was a shift in the metabolism of the pigs which happened to ada- pt the animals to the physiological needs of fasting. 3.Although the tendency of changes in all the criteria analyzed was about the same in both groups of pigs,it varied in degrees of some criteria.Thus in the beginning of fasting,both the decreasing in blood glucose and the increasing in plasma FFA of the pigs ingesting more water appeared to be quicker than those of the pigs ingesting less wa- ter.After fasting for about 36 hours both the increase in blood glucose and decrease in plasma FFA of the pigs ingesting more water were quicker than those of the pigs ingesting less water while the increase in blood lactic acid of the pigs ingesting more water was slower. There was no significant difference between these 2 groups in the rates of decrease and increase in the amount of the urinary nitrogen. What the above differences in metabolism between these two groups meant could not yet be explained completely,but at least we could see that when it is necessary,the activity of gluconeogenesis of the pigs ingesting more water was more intensive than that of the pigs ingesting less water and the former could mobilize fat more quickly in order to reserve carbohydrate.The facts that the rates of changes in urinary nitrogen were the same in both groups showed that the amo- unt of water intake had no effect on the mobilization of body protein during fasting. 4.The ingesting action might increase the blood glucose level and decrease the plasma FFA level suddenly,but the extent of increase in blood glucoselevel was lesser in the pigs ingesting more water than in the pigs ingesing less water.