Effect of Dietary Energy Intake on Protein Deficiency Symptoms and Body Composition of Baby Pigs Fed Equalized but Suboptimal Amounts of Protein

Abstract

Yorkshire pigs weaned at 3 to 5 weeks of age, weighing an average of 7.2 kg initially in experiment 1 and 4.9 kg in experiment 2, were pair-fed 3% protein purified diets containing 5 or 25% corn oil. The daily feed intake of the member of each pair fed the low fat diet was equalized with the ad libitum consumption of its mate fed the high fat diet. The total calorie consumption per pig was approximately 29% greater in the high fat group than in the low fat group. A similar diet containing 24% protein was fed as a positive control diet at a level of 4.5% of body weight daily in experiment 1 and 4.0% in experiment 2. Total serum protein level and percentage of albumin decreased significantly (P < 0.01) after feeding the low protein diets for 8 weeks. Pigs fed the low protein-high fat diet showed a more severe depression in serum proteins than those fed the low protein-low fat diet even though protein intake was equal for the 2 groups. Liver lipid concentration was 34.1% in the pigs fed low protein-high fat as compared with 9.7% in those fed low protein-low fat and 12.3% in positive control pigs. Pigs in the former group developed typical kwashiorkor-like symptoms, including severe edema in the umbilical and genital regions and general feebleness and apathy. In contrast, pair-fed mates fed the low protein-low fat diet failed to develop these symptoms and remained thin in appearance and active, indicating 2 different manifestations of protein deficiency, one resembling kwashiorkor, the other marasmus. Gross energy concentration of whole empty bodies of pigs fed the 2 low protein diets was similar (6.5 vs. 6.2 kcal/g of dry sample) but that of positive control pigs was significantly lower (P < 0.01) (5.6 kcal/g). This similarity in energy storage in the 2 low protein groups, despite the 29% difference in calorie intake, indicates not only an increased specific dynamic effect with low protein diets, but an additional increase when greater calorie intake accompanies protein deficiency.