COBIA (Rachycentron canadum)

showed that SWM could not enhance cobia resistance to Photobacterium damselae ssp. piscicidainfection. Our results suggest that the administration of a 10% SWM diet could potentially reducethe use of FM in the diet of cobia.237. Lunger, A.N., McLean, E. & Craig, S.R. (2006). Replacement of fish meal in cobia(Rachycentron canadum) diets using an organically certified protein. Aquaculture, 257(1-4), 393-399.A six-week feeding trial was conducted to evaluate the use of a yeast-based, certified organicprotein source as a replacement for fish meal in diets for cobia. Five experimental diets wereformulated to provide 40% crude protein and 11% dietary lipid (dry matter basis) with the yeastbasedprotein source replacing Special Select (R) menhaden fish meal at 25%, 50%, 75% and 100%of dietary protein. Ten juvenile cobia (initial weight 11.5 g/fish) were randomly stocked in triplicate300 l circular fiberglass tanks (n=30 treatment -1 ) and hand-fed the diets based upon total tankbiomass two times daily at 0900 and 1400 h. Fish were group weighed weekly to monitorperformance and adjust feeding rations. Water temperature and salinity were maintained at 27 °Cand 15‰, respectively. At the end of the feeding trial, weight gain, ranging from 86% to 512%, andfeed conversion ratio values, ranging from 1.9 to 5.8, were significantly affected by the inclusion ofthe yeast-based protein source, with decreasing values as inclusion levels of the yeast-based proteinsource rose above 25% of dietary protein. Cobia fed the diet containing 25% of dietary protein fromthe yeast-based protein source had equal weight gain and feed conversion ratio values as fish fedthe control diet composed of 100% fish meal (503 vs. 512 and 1.9 vs. 1.9, respectively). Biologicalindices including hepatosomatic index, visceral somatic index and muscle ratio were all similarlyaffected by inclusion of the yeast-based protein source, with significant impacts when inclusionlevels rose above 25% of dietary protein. As with the weight gain and feed efficiency ratio values,fish fed the diet containing 25% of protein from the yeast-based source had similar values as thoseobserved in the control animals. This study represents the first attempt to utilize an organicallycertified protein source as a replacement for fish meal in diets for juvenile cobia. Although levels ofinclusion of the yeast-based protein source above 50% of dietary protein resulted in detrimentaleffects on production characteristics, the data clearly suggest that, at a minimum, 25% of dietaryprotein can be provided by this yeast-based protein in diets for cobia.238. Lunger, A.N., McLean, E. & Craig, S.R. (2007). The effects of organic protein supplementationupon growth, feed conversion and texture quality parameters of juvenile cobia (Rachycentroncanadum). Aquaculture, 264(1-4), 342-352.An eight week feeding trial was conducted to examine the impacts of organically certifiablealternate protein sources on growth, feed efficiency, biological indices, fillet proximate compositionand fillet quality in juvenile cobia. Diets were formulated to be isonitrogenous and isocaloric. Thecontrol diet provided 45% crude protein from Special Select (R) menhaden fish meal and 10% totallipid. The remaining diets were formulated with 25 and 40% inclusion of NuPro (R) (an organicallycertified yeast-derived protein source), and 40% inclusion of organically certified soybean meal,soybean isolate, or hemp seed meal. Two additional diets were formulated to contain a mixture ofall organic protein sources at 23% with 8% fish meal or 25% and no fish meal. Diets were fed totriplicate groups of juvenile cobia (initial weight 10 g/fish) in 300 L circular tanks connected as partof a recirculating aquaculture system. Weight gain ranged from 167 to 1138% increase from initialweight and was similar for all fish fed diets containing 40% of any given alternate protein source.Fish fed the blended diet with 8% fish meal exhibited significantly lower weight gain, SGR, and FEratio values than all other fish. Cobia fed the diet without any fish meal did not survive to the end ofthe study. Biological indices such as muscle ratio (MR), visceral somatic index (VSI), and packedcell volume (PCV) were all similar between fish fed the control diet and those fed diets with up to40% alternate protein. Fish fed the diet with only 8% fish meal had significantly lower MR, PCV,and plasma protein, and significantly higher VSI. All fish exhibited similar fillet proximatecomposition for protein, lipid, dry matter, and ash except for those fed the diet containing 8% fishmeal. Alternate protein source did appear to impact the fillet texture of cobia. Generally speaking,plant protein sources returned higher textural characteristics than the fish meal control. At all timepoints and all texture parameters, cobia fed the diet containing hemp seed meal returned the highestvalues except for distance to rupture in the final time point. Results indicate that up to 40% fishmeal protein can be replaced by any of the organically certifiable alternate proteins that were usedin this study without detrimental impacts to weight gain, feed efficiency, biological indices, or filletcomposition in juvenile cobia. Our results also suggest that alternate proteins have differential72