|Li, M -|
|Robinson, E -|
|Tucker, C -|
|Oberle, D -|
Submitted to: Journal of the World Aquaculture Society
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: November 1, 2008
Publication Date: January 1, 2009
Citation: Li, M.H., Robinson, E.H., Tucker, C.S., Oberle, D.F., Bosworth, B.G. 2009. Comparison of Channel and Blue Catfish Fed Diets Containing Various Levels of Protein. Journal of the World Aquaculture Society. 39:646-655. Interpretive Summary: Channel catfish represent perhaps 99% of commercially grown catfish in the USA. They possess a number of good qualities for aquaculture, including rapid growth, ease of spawning, tolerance to wide ranges of temperature and water quality, good product quality, and high consumer acceptance of the product. However, channel catfish have relatively non-uniform within-population growth rates, are adept at evading capture by seining, and are susceptible to certain species-specific diseases that cause millions of dollars in losses annually. As a result of increasing losses of channel catfish to diseases, and a partial return of the industry to single-batch culture, there has been renewed interest in the culture of blue catfish as an alternative aquaculture species. Development of blue catfish as a commercially significant aquaculture species will rely on adequate knowledge of the species nutritional requirements and proper feeding practices. Results from this study show that blue catfish can be successfully cultured in ponds under conditions similar to channel catfish, but there are some issues that may affect relative economic performance. The two main factors that we evaluated in our study indicate that blue catfish appear to require a higher dietary protein level and that fillet yield was reduced compared with channel catfish. Although total meat yield was higher in blue catfish, the primary market for catfish is the fillet market. A small difference in fillet yield can result in a considerable cumulative loss of revenue for catfish processors. Other factors that should be considered when evaluating blue versus channel catfish is the increased cost associated with the longer period to maturation and the potential benefits of increased resistance of blue catfish to diseases such as enteric septicemia of catfish, proliferative gill disease, and channel catfish virus disease reported in the literature.
Technical Abstract: A comparative study was conducted on growth and protein requirements of channel catfish, Ictalurus punctatus, and blue catfish, Ictalurus furcatus. Four diets containing 24, 28, 32, or 36% protein were fed to both channel (initial weight 6.9 g/fish) and blue (6.6 g/fish) catfish for two growing seasons. There were significant interactions between dietary protein and fish species for weight gain and feed conversion ratio (FCR). No significant differences were observed in weight gain of channel catfish fed various protein diets, whereas higher protein diets (32 and 36%) resulted in better weight gain in blue catfish than lower protein diets (24 and 28%). No consistent differences were observed in the FCR of channel catfish fed various levels of dietary protein, whereas significantly higher FCRs were noted in blue catfish fed the 24 and 28% protein diets compared with fish fed 32 and 36% protein diets. Regardless of dietary protein levels, blue catfish had higher carcass, nugget, and total meat yield, and higher fillet moisture and protein, but lower fillet yield and fillet fat. Regardless of fish species, fish fed the 36% protein diet had higher carcass, fillet, and total meat yield than fish fed the 28 and 32% protein diets, which in turn had higher yields than fish fed the 24% protein diet. It appears that blue catfish can be successfully cultured by feeding a 32% protein diet.