The effect of feeding level and physiological status on total flow and amino acid composition of endogenous protein at the distal ileum in swine

An experiment was conducted to investigate the effects of BW, feed intake, and the physiological condition of the animal on the loss and amino acid co mposition of endogenous protein in swine. Ten growing barrows and five mult iparous sows were equipped with a T-cannula in the distal ileum for digesta collection. A protein-free diet was fed to all animals. The barrows were g iven free access to the experimental diet. The sows:also were allowed to co nsume the diet on an ad libitum basis, and digesta were collected during la ctation and in the following gestation period. In addition, digesta from th e gravid sows were collected after restricting the sows to 2 kg of feed per day. For each animal group, the endogenous losses-of protein and aminoacid s were calculated in relation to DMI, and the amino acid composition of end ogenous protein was calculated. The total endogenous gut protein loss at th e distal ileum of growing pigs, lactating sows, and gestating sows, given f ree access to feed, was 12.4, 9.4, and 11.2 g/kg DMI, respectively. These v alues were not different (P >.10). However, when gestating sows were fed on ly 2 kg/d, 17.8 g of endogenous protein was lost per kilogram of DMI which was higher ( P < .05) than for any of the other groups. This difference was mainly caused by higher (P < .05) losses of glycine, proline, and serine. There were no differences (P > .05) in amino acid composition of endogenous protein between growing pigs, lactating sows, and gestating sows given fre e access to feed, but restricted-fed gestating sows had an amino acid compo sition of endogenous protein that was significantly different from that of the other groups. The results from the experiment showed that age, BW, and the physiological condition of the animal have little or no effect on the a mount of endogenous protein and amino acids lost at the distal ileum of hog s if calculated in relation to DMI. Likewise, the amino acid composition wa s not affected by the BW or physiological condition of the animal. However, DMI had a significant effect on endogenous protein losses; in sows as well as on amino acid composition of endogenous protein.