COBIA (Rachycentron canadum)

258. Sun, L., Chen, H. & Huang, H. (2010). Effects of ration level and feed type on growth andnitrogen budget of young cobia (Rachycentron canadum). Journal of Tropical Oceanography,29(4), 94-101.Growth and nitrogen budget of young cobia (initial body weight 28g in average) at different rationlevels(from starvation to satiation) for different feed types(i.e.NSF-natural sardine fish,CEFFcommercialeel formulated feed and CMFF-commercial marine-fish formulated feed) were studied,and the relationships between growth as well as nitrogenous excretion and ration were establishedin this paper. The results showed that as ration increased specific growth rate (SGR) of young cobiaincreased with a decelerating pattern for NSF and CEFF and with a linear pattern for CMFF.Among three feed type groups young cobia had a similar SGR between NSF and CEFF, but theSGR for NSF and CEFF was much higher than that for CMFF.259. Sun, L., Chen, H., Huang, L. & Wang, Z. (2006). Growth, faecal production, nitrogenousexcretion and energy budget of juvenile cobia (Rachycentron canadum) relative to feed type andration level. Aquaculture, 259(1-4), 211-221.Growth, faecal production, nitrogenous excretion and energy budget of juvenile cobia (initial bodyweight similar to 28 g) at different ration levels (RL, % per day) ranging from starvation to adlibitum for three feed types, i.e., natural sardine fish (NSF), commercial eel formulated feed (CEFF)and commercial marine-fish formulated feed (CMFF), were investigated in this study. Both feedtype and ration level affected significantly faecal production (f, mg g -1 day -1 ), and nitrogenousexcretion (u, mg g -1 day -1 ). Feed type, not ration level, for the NSF-fed and CEFF-fed groups andboth feed type and ration level for the CMFF-fed group affected significantly feed absorptionefficiency (FAE, %). For each feed type group, faecal production and nitrogenous excretionincreased whereas feed absorption efficiency in dry weight (FAE d , %), protein (FAE p , %) andenergy (FAE e , %), with a small variation, tended to decrease as ration increased. Specific growthrate in wet weight (SGR w , % per day), dry weight (SGR d , % per day), protein (SGR p , % per day)and energy (SGR e , % per day) for the NSF-fed and CEFF-fed groups was much higher than that forthe CMFF-fed group, and the growth-ration relationship was a decelerating curve described as alogarithmic equation for the NSF-fed and CEFF-fed group, and a linearity described as a simpleequation for the CMFF-fed group. There was a significant difference of the slopes in the regressionequations among three feed type groups by analysis of covariance. Multiple regression analysisshowed that the relationships between specific growth rate (SGR, % per day) and ration level in dryweight (RL d , % per day) as well as feed type (D1 D2) were SGR sub w =-2.226+4.022ln(RL d +1)-0.895D1-2.705D2, SGR d =-2.686+4.422ln(RL d +1)-1.014D1-2.969D2, SGR p =-2.481+4.316ln(RL d +1)-1.122D1-2.943D2 and SGR e =-3.239+4.972ln(RL d +1)-0.954D1-3.053D2.Feed conversion efficiency in wet weight (FCE w , %), dry weight (FCE d , %), protein (FCE p , %) andenergy (FCE e , %) for the NSF-fed and CEFF-fed groups was much higher than that for the CMFFfedgroup, and with increased ration FCE increased or first increased then decreased for the NSFfedand CEFF-fed groups and increased significantly for the CMFF-fed group. Energy budgets ofjuvenile cobia at satiation ration were 100A=59R+41G for NSF-fed group, 100A=67R+33G forCEFF-fed group and 100A=83R+17G for CMFF-fed group, where A is assimilated energy R isenergy spent in metabolism and G is energy stored as growth.260. Sun, L., Chen, H., Huang, L., Wang, Z. & Yan, Y. (2006). A primary study on feeding techniqueof cobia (Rachycentron canadum) during artificial breeding. Journal of Tropical Oceanography,25(2), 24-30.Suitable feeding schedule and ration level for young cobia (Rachycentron canadum) weighingabout l0 g were established by studying their diel feeding rhythm and body composition, specificgrowth rate and food conversation efficiency at different ration levels. An obvious diet feedingrhythm of young cobia was observed. Feeding mainly proceeded by day and was most active duringthe periods of 06:00-08:00 and 18:00-20:00, forming two feeding peaks in a day. Feeding decreasedremarkably in the darkness of night and no feeding happened during the period of 00:00-04:00,which formed a feeding vale in a day. Thus it could be seen that the feeding rhythm of young cobiawas characterized by daytime feeding and inclined to twilight feeding. Five ration levels (RL) wereset as follows: starvation, 3%, 6 % and 9% of initial body weight per day, and satiation. The proteinand lipid contents in the body of young cobia generally increased with increased ration, with amarked decrease of lipid content at 6% ration and no significant difference of protein content from3% to satiation ration.80