Effect of Fat Level in Isonitrogenous Diets on the Composition of Avian Pancreatic Juice

Abstract
Each of 12 male commercial-strain chickens was prepared with a permanent cannula of the main pancreatic duct. Two groups of six birds were fed diets containing 14.5% or 4.5% fat for three 4-day periods in two dietary sequences in a double reversal experimental design. All chickens were continued for a postexperimental period of 9 days and were fed the diet they were receiving on day 12 of the experimental period. The continuous secretion of pancreatic juice was collected daily, frozen and stored at - 20°. All samples of pancreatic juice were analyzed for total protein content, and for lipase, amylase, trypsin and chymotrypsin activity. Significantly (P < 0.01) more of the low fat diet than of the high fat diet was consumed by the chickens. The volume of pancreatic juice secreted was not significantly influenced by diet regimen. Feeding the high fat diet significantly (P < 0.01) decreased the total protein concentration of the pancreatic juice. The level of specific lipase in the pancreatic juice was significantly (P < 0.01) augmented by increasing the dietary fat intake. Increased intakes of carbohydrate and protein, resulting from feeding the low fat diet, significantly (P < 0.01) increased the specific amylase activity and the specific trypsin and chymotrypsin activities of pancreatic juice. The enzyme activity data for the postexperimental period substantiated the observations of the 12-day experimental period. Chymotrypsin activity was consistently higher than trypsin activity in all samples of pancreatic juice. The feeding of the high fat diet, however, tended to lower the chymotrypsin/trypsin ratios.