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Effect of early postnatal long-term fasting on the development of peptide hydrolysis in chicks
1Institute of Biology, Latvian Academy of Sciences, U.S.S.R..
Insights
Early peptide hydrolysis in chicks depends on nutrition. Starvation affects digestive enzyme activity, with exogenous nutrition crucial for developing intestinal exopeptidase gradients and efficient peptide breakdown.
Area of Science:
- Physiology
- Biochemistry
- Digestive System Development
Background:
- Peptide hydrolysis is essential for nutrient absorption in newly hatched chicks.
- Understanding the early development of digestive enzymes is critical for avian nutrition.
- The impact of nutritional status on digestive enzyme activity in early postnatal life requires elucidation.
Purpose of the Study:
- To investigate the early development of peptide hydrolysis in chick digestive tracts.
- To determine the effects of fasting and feeding on key digestive enzyme activities.
- To explore the role of exogenous nutrition in establishing digestive enzyme gradients.
Main Methods:
- Experimental study on fasted and fed chicks during the first 10 days post-hatch.
- Assays for pancreatic carboxypeptidase A (CPA) activity.
- Measurement of aminopeptidase (AP) and dipeptidase activities in the small intestine.
Main Results:
- Pancreatic CPA activity peaked at hatch, then decreased, but increased significantly with prolonged starvation.
- Intestinal aminopeptidase activity showed a delayed response to starvation, while dipeptidases were highly sensitive, increasing after 24 hours of fasting.
- A proximo-distal gradient of intestinal exopeptidase activities formed only after the initiation of feeding.
Conclusions:
- Peptide hydrolysis development is influenced by both chick age and the initiation of exogenous nutrition.
- Starvation significantly alters the activity of key digestive enzymes, with varying sensitivity among different enzyme classes.
- The establishment of a functional digestive system capable of efficient peptide hydrolysis is dependent on timely feeding.
Abstract:
1. Early development of peptide hydrolysis in the digestive tract was investigated in experiments with fasted and fed ad lib. chicks during the first decade of postnatal period. 2. Pancreatic carboxypeptidase A (CPA) activity was maximal at the moment of hatch. On the second day CPA activity considerably diminished in starved and fed animal groups; further starvation (3-4 days) led to the significant increase of CPA total and specific activity, whereas the amount of enzyme in pancreas of fed chicks was rather low. 3. Aminopeptidase (AP) activity of the small intestinal surface was less sensitive to starvation. The increase of activity in all intestinal parts was observed only on the 4th day of fasting. The most sensitive to starvation were dipeptidases. Changes in their activity (2-fold increase) were detected after 24 hr of starvation. 4. The formation of specific physiological proximo-distal gradient of intestinal exopeptidase activities began only after the moment of the first feeding. 5. This gives evidence that the development of peptide hydrolysis depends not only on the age of the animal but also on the normal physiological beginning of the process of exogenous nutrition.