Mise en évidence et valorisation de la croissance compensatrice chezHeterobranchus longifilis

Abstract

Accepté le 12 avril 1995. Abstract RésuméLuquct P., Z. J. Otémé, A. Cissé. Aquat. Living Resour., 1995, 8, 389-394. Evidence for ct>rnpensutov growth and its urility in the culture cf Heterobranchu~ longifilis.Three trophic levels wcre tested with the African catfi\h IIvterobranchus 1ongiJili.s. In thc 1st trial, fish with a rriean weight of 60 g (12 batchcs of 8 fish), were subjcctcd to severely restrictcd feeding (1% of body weight) for three weeks, then incrcased rations for thrcc weeks either to ad libitum feeding or to 3% of body wcight. Growth sates wcrc compared to thosc of fish that had becn continuously fed eithcr ud libitum or at 3% of body wcight. Although the final live weights of fish on restricted diets were lower than those of fi5h on unrestrictcd diets, the results indicate that a restrictive feeding rate ultimately induces a significantly higher specific growth rate, and a better food conversion ratio. This compensatory growth is caused both by hypcrphagy and by an improved metabolism. A positive effect of hyperphagy was still noted during the following two weeks.During the 2nd experirnent, silurids of an initial mean weight of 141 g (6 batchcs of 18 fish) werc fed for 10 weeks either at a constant rate of 4% body weight, or fed altemately on a diet restrictcd to 2% of body weight for one wcck then increased to 4 or 5% of body weight for the next week. At the end of the trial (10 weeks), mcan weights were not significantly difLerent. The best food convcrsion ratio (1.8) was found among the fish on restricted dicts alternated with increased rations equal to that of the control (4%). In the 3rd experiment, silurids of a mean weight of 340 g (6 batches of 16 fishes) were fed for five months at a constant rate of 3% of body weight and those of fish fed altcmately at 2% then 4% using 15-day intervals following lunar cycles were compared. At the end of the experiment, final mean wcights varied from 977 to 1 127 g, while the food conversion ratios varied from 2.1 to 2.5. The best performances, considcring al1 critena, were those of group of fish fed restricted diets of 2% of body weight during the waning moon and then incrcased to 4% during the waxing moon. Conversely, the worst results were obtained with those fish on a restricted diet during the waxing moon. To fully utilize the phenomenon of compensatory gain as illustrated in the silurid, dietary restriction, even a mild one for a one wcek period can be recommended. However, there appears to be very little profit in attempting to benefit from hyperphagy after restricted diets for two weeks.Keywurds: African catfish, Heterobrunchus longifilis, diets, growth, lunar cycles.Trois niveaux trophiques ont été expérimentalernent étudiés chez le silure africain Heterobranchus longijîlis. Au cours d'un 1" essai, des poissons d'un poids moyen initial de 60 g ont été rationnés (1 % du poids vif) pendant trois semaines puis alimentés pendant 3 semaines soit ad libitum soit à 3 % du poids vif. Leur croissance a été comparée à celle de poissons nourris en perm...

Daily activity rhythms of the African catfishHeterobranchus longifilis(Clariidae) in an experimental enclosure

“…Others studies even mention periods of food restriction as long as 3 weeks (e.g. Luquet et al 1995). The same methodology as in Experiment 1 was used here.…”

Nouvelles espèces de poissons-chats pour le développement de la pisciculture africaine

“…Un poid, moyen de 500 à 700 g est atteint en 6 mois ce qui pcrmet de rkaliser deux cycles de grossissement par an. Les besoins alimentaires, notamment les besoins en protéines (Kerdchuen, 1992), de même que les stratégies d'alimentation (Kerdchuen, 1992 ;Luquet et al, 1995 ;Avit et Luquet, 1995) ont Cté déterminCs. I,cs modalités dc distribution des aliments constituent un facteur important d'uptirriisation de la croissance et des indices de consommation.…”

Testicular structure, spermatogenesis and sperm cryopreservation in the African clariid catfish Heterobranchus longifilis (Valenciennes, 1840)

“…Extensive work has been reported on its nutrition and feeding (Kerdchuen & Legendre 1991;Kerdchuen 1992;Oteme & Gilles 1995). Other aspects of the biology and the culture of H. longifilis, including the effects of water chemistry on growth and survival, and the optimization of growth and feed con\'ersion rates, have recently been investigated (Luquet, Oteme & Metongo 1993;Luquet. Oteme & Cisse 1995).…”