Theses and Dissertations


Name: Hedrick, Ryan L.

Degree: MS

Chair: Thomas Popma


University: Auburn University

Location: Auburn, Alabama

Date: 2002

Pages: 44

Keywords: Channel catfish,dietary protein,lipids,fatty acids,feed conversion


Three protein sources were evaluated as supplements to grow-out feeds for mixed-size channel catfish (Ictalurus punctatus) stocked at 16,750 fish/ha in 0.04-ha earthen ponds. Meat, bone, and blood meal were used in the diet containing terrestrial animal protein (MBM). Menhaden fishmeal was used for the diet containing fish protein (FM). Soybean meal and wheat (lysine added) was used for the all-vegetable diet (AV). All feeds had similar digestible energy to protein ratios, and the Lysine and methionene+cystine requirements were exceeded. Fingerling channel catfish (average size: 3-5 inches) made up 90% of the fish stocked/pond. Sub-market size channel catfish (average size: 12-14 inches) made up the remaining 10% of the fish/pond. Each of the three practical-type feeds were assigned for six replicate ponds. The fish were fed to satiation once daily for 133 days. No significant differences were seen among treatments for evening dissolved oxygen (P = 0.24), average morning dissolved oxygen (P = 0.27), and temperature (P = 0.85). For total fish harvested, dietary protein did not affect the weight gain, hepato-somatic index, percent survival, harvest yield, protein efficiency ratio, percentage of interperitineal fat, and dress-out percentage. Feed consumption, and feed conversion ratio were significantly higher (P < 0.04) in fish fed the MBM diet. However, this response could be contributed to the lower protein percentage or less digestible energy of the MBM diet compared to the FM and AV diets. This diet also produced a significantly lower percentage of lipids in the fillets. Significant differences were shown for fatty acids found in the fillets of large fish and small fish fed all diets. The large fish showed a significant difference in Myristic acid, 16:ln7, and 16:2714 content in fillets. A significant difference was shown for linolenic acid (18:3n3) content in the fillets from large fish where fillets from fish fed FM and MBM diets had similar 18:3n3 contents, but 18:3n3 content in fillets of both were lower in comparison to the fillets of fish fed the AV diet. The small fish also exerted some significant differences in the fatty acid profile of fillets for 16:717, 20:5713, and 22:5713. A size related significant difference was found for the total saturated fatty acids where values for the fillets of small fish were lower than those of large fish. Conversely, a size-related significant difference was found for the total monounsaturated fatty acids in the fillets, where the large fish had lower levels than the small fish. When the fatty acids found in the fillets were classified as total polyunsaturated fatty acids, total omega-3 fatty acids, or total omega-6 fatty acids no significant differences in concentrations due to diets were found. This suggests that all three protein sources performed similarly, and that vegetable meal is a suitable alternative to animal and fish protein sources.

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