VOLATILE FATTY ACIDS AND LACTIC ACID IN THE ALIMENTARY TRACT OF THE YOUNG PIG

A total of 208 digesta samples from the stomach, small intestine, caecum and colon of 79 piglets killed between 1 and 9 weeks of age were analysed for volatile fatty acids (C1 – C5) and lactic acid.The total concentration of the acids in the large intestine ranged from 11 to 29 meq./100 ml. fluid which generally exceeded that in the stomach and small intestine. As the pigs aged, concentration tended to decrease in the upper sections and increase in the lower section of the tract. The addition of whey to a basal "creep" ration, fed from 3 weeks of age, had no apparent effect on the concentration of acids.Formic acid was found only in the small intestine. Increased proportions of acetic and propionic acids in the stomach of the 5-week-old pig indicated dietary effects due to the introduction of solid feed. Lactic acid proportions were from zero in the large intestine to 95 per cent in the stomach. The proportions of lactic acid in the stomach and small intestine of pigs at 9 weeks was markedly higher than at 7 weeks when weaned. Antibiotic (100 gm. chlortetracycline/ton) added to the whey ration fed to 4 pigs from 7 weeks of age gave increases in concentration which were significant (P < 0.05) only in the stomach. The proportion of acids was not altered by antibiotic in the feed.