The nutritional and genetic effects on body growth, reproduction and molecular mechanisms responsible for muscle growth in yellow perch Perca flavescens.

摘要

The goal of the present project was to gain a better understanding of nutritional and genetic effects on the body growth, reproduction, and molecular mechanisms responsible for muscle growth and development in yellow perch Perca flavescens. In order to understand this phenomenon the following five experiments were accomplished.;The first study described in Chapter 2 determined the optimum diet for the grow-out phase of juvenile yellow perch. The results of this experiment suggested that lysine (Lys) affects the growth and plasma free amino acid (FAA) pools in yellow perch. Furthermore, these results suggested that wheat-gluten based diets supplemented with Lys could be a good source of protein to improve the growth performance of this species.;The second and third studies described in Chapters 3 and 4, respectively, determined whether Lys supplementation influences the maturation and sperm and egg quality in yellow perch. These studies showed that dietary Lys level affects sperm parameters (spermatozoa concentration, motility, seminal plasma protein concentration, trypsin inhibitor activity, seminal plasma FAA concentration) and egg quality (FAA level). These studies also found that the effect of female dietary treatments on the egg fertilization rate was dependent on the dietary treatment of males. This is the first report demonstrating the effect of dietary Lys levels in plant protein-based diets on quality of yellow perch gametes and therefore, reproduction of this species. These results also showed a possibility for the improvement of reproductive success of yellow perch by dietary manipulations with different protein sources and amino acid supplements.;The fourth study described in Chapter 5 examined the effect of a fish meal and wheat-gluten-based diet supplemented with Lys in the form of the free amino acid or as part of a dipeptide, on growth, intestine oligopeptide transporter, PepT1, transcript levels, and muscle protein expression in yellow perch juveniles. The results showed increase in PepT1 mRNA transcript levels associated with dipeptide supplemented diets. The full-length cDNA, representing yellow perch PepT , was cloned and sequenced (GeneBank: accession no. GQ906471). Proteomic fingerprinting found 13 electrophoretically resolved protein/peptide bands from the muscle sarcoplasmic fraction different across groups suggesting that muscle protein expression was influenced by dietary treatments.;Finally, the fifth study described in Chapter 6 compared skeletal muscle proteomic fingerprint profiles of fast- vs. slow-growing yellow perch and identified the proteins that were associated with fish growth. The statistical analyses found 18 electrophoretically resolved protein/peptide bands with higher staining intensity in slow-growers, and 8 with higher intensity in fast-growers. Primary protein sequence analysis using nano-LC/MS/MS identified 9 proteins. This is the first report identifying gene products in fast- and slow-growing yellow perch associated with growth of skeletal muscle. The identification of such gene products that contribute to skeletal muscle growth superiority in fish under controlled conditions could become a biomarker based tool for the selection of broodfish with the potential for increased protein accretion associated with rapid muscle growth, and hence, the production of larger fish.