The assessment of protein quality of carp (Cyprinus carpio) diets

Protein quality of carp diets was assessed by five methods: 1. True digestibility, true NPU, BV (as percentage) and PER were determined for approximately iso-energetic diets containing ca.38% protein from 4 different sources. Fish meal gave values of 94.0, 72.5, 77.0, and 1.21 respectively; egg 93.0, 65.4, 70.3, 1.26; Pruteen 68.4, 63.6, 68.40, 1.36; and Casein 91.0, 56.90, 62.5, 1.33. 2. Blood urea were determined and found to be significantly increased with increasing protein concentration in the diet. 3. Ammonia excretion rate was determined; it increased with a decline in protein quality, being greater on groundnut, rapeseed meal, and sunflower diets than on fishmeal, cottonseed meal, and pruteen. 4. Protein sources were incubated in vitro with digestive fluids of fish. Protein digestibilities for fishmeal diets containing 14 and 27% protein were 90.2 and 93.0% respectively; casein (18 and 36%), 91.5 and 93.2%; soybean (10 and 20%), 84.2 and 85.3% ; sunflower (8 and 16%), 64.2 and 66.1%; and fish meal plus soybean meal (ca. 18.2%) 86.5. 5. Plasma free amino acids were individually determined at 0, 6, 24 and 48 h after force-feeding diets containing 15 and 30% protein from six different sources. Total free AA were highest at 24 h for casein and fishmeal, and at 48 h for egg, soybean, rapeseed and sunflower. The 24 h essential amino acid indices (EAAI) for the six diets at 15% protein were, in the same order, 93.0, 100, 100, 86.4, 62.4, and 97.2. At 30% protein, the 24 h EAAI were 78.5, 84.3, 100, and 83.8 for casein, fishmeal, egg, and rapeseed respectively.

Appetite regulatory mechanisms and food intake in mice are sensitive to mismatch in diets between pregnancy and postnatal periods

Human and animal studies suggest that obesity in adulthood may have its origins partly during prenatal development. One of the underlying causes of obesity is the perturbation of hypothalamic mechanisms controlling appetite. We determined mRNA levels of genes that regulate appetite, namely neuropeptide Y (NPY), pro-opiomelanocortin (POMC) and the leptin receptor isoform Ob-Rb, in the hypothalamus of adult mouse offspring from pregnant dams fed a protein-restricted diet, and examined whether mismatched post-weaning high-fat diet altered further expression of these gene transcripts. Pregnant MF1 mice were fed either normal protein (C, 18% casein) or protein-restricted (PR, 9% casein) diet throughout pregnancy. Weaned offspring were fed to adulthood a high-fat (HF; 45% kcal fat) or standard chow (21% kcal fat) diet to generate the C/HF, C/C, PR/HF and PR/C groups. Food intake and body weight were monitored during this period. Hypothalamic tissues were collected at 16 weeks of age for analysis of gene expression by real time RT-PCR. All HF-fed offspring were observed to be heavier vs. C groups regardless of the maternal diet during pregnancy. In the PR/HF males, but not in females, daily energy intake was reduced by 20% vs. the PR/C group (p <0.001). In PR/HF males, hypothalamic mRNA levels were lower vs. the PR/C group for NPY (p <0.001) and Ob-Rb (p <0.05). POMC levels were similar in all groups. In females, mRNA levels for these transcripts were similar in all groups. Our results suggest that adaptive changes during prenatal development in response to maternal dietary manipulation may have long-term sex-specific consequences on the regulation of appetite and metabolism following post-weaning exposure to an energy-rich nutritional environment. © 2008 Elsevier B.V. All rights reserved.