Location: Warmwater Aquaculture Research UnitTitle: Effects of feeding frequency on apparent energy and nutrient digestibility/availability of channel catfish, Ictalurus punctatus, reared at optimal and suboptimal temperatures Author
|Li, Menghe - MISSISSIPPI STATE UNIVERSITY|
|Lucas, Penelope - MISSISSIPPI STATE UNIVERSITY|
Submitted to: Journal of the World Aquaculture Society
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 5/4/2016
Publication Date: 2/1/2017
Citation: Li, M., Lucas, P. 2017. Effects of feeding frequency on apparent energy and nutrient digestibility/availability of channel catfish, Ictalurus punctatus, reared at optimal and suboptimal temperatures. Journal of the World Aquaculture Society. 48(1):132-136.
Interpretive Summary: Pond-raised channel catfish during food fish production are generally fed once daily to apparent satiation for optimum growth. However, during periods of low fish prices and high feed cost which have occurred periodically in the past, catfish may be fed every other day (EOD) as a management tool to reduce feed and production costs. Previous studies have shown that EOD feeding improves feed conversion ratio (FCR) of pond-raised channel catfish, which was thought to be related at least in part to less feed wastage because there is less chance to waste feed when fish are fed EOD in commercial ponds. It has also been speculated that fish fed EOD may digest the feed more efficiently than those fed daily. The gut retention time of the diet in fish fed EOD may be extended, resulting in nutrients being more efficiently digested and absorbed. It has been demonstrated that postprandial starvation increases gut retention time of diet, and reducing daily feeding frequency has also been reported to increase gut retention time and nutrient digestibility and utilization efficiency in fish. On the other hand, as the feeding frequency decreases, animals generally ingest a larger quantity of feed to compensate for less frequent feeding. Nutrients in a large meal might not be as effectively digested and absorbed because of limited exposure of the diet to digestive enzymes. Results from this study demonstrate channel catfish can digest dietary protein and energy equally well whether they are fed once daily or EOD to apparent satiation. While channel catfish consumed less diet at 24 C than at 30 C, they had a similar efficiency digesting protein and energy.
Technical Abstract: This study examined the effects of feeding frequency (daily versus every other day [EOD]) on nutrient digestibility/availability of channel catfish, Ictalurus punctatus, reared at optimal (30 C) and suboptimal (24 C) temperatures. A 28% protein practical diet was used as the test diet, and chromic oxide was used at 0.75% of the diet as a maker. Twenty channel catfish of a mean weight of 141 g/fish were stocked into 12 flow-through aquaria (110 L). Fish were fed daily or EOD to apparent satiation for 7 d before fecal samples were collected by the dissection method. Fish fed EOD to apparent satiation consumed more diet on days fed than those fed daily, and fish reared at 30 C consumed more diet than those reared at 24 C. Neither feeding frequency nor water temperature significantly affected apparent digestibility coefficients for energy and protein and apparent availability coefficients for total amino acids. Results show no advantage by feeding EOD over feeding daily on nutrient digestibility and diet utilization efficiency.