Effect of conjugated linoleic and docosahexaenoic acids on growth of juvenile tilapia Oreochromis niloticus

Abstract

The present study was conducted to investigate the effects of dietary conjugated linoleic acid (CLA)-and conjugated docosahexaenoic acid (CDHA)-supplemented diets on the growth and body lipid composition of tilapia Oreochromis niloticus . Four dietary treatments of linoleic acid (LA), CLA, docosahexaenoic acid (DHA) and CDHA were tested in this experiment over a feeding period of 9 weeks. The initial average body weight and length of fish were 4.53 ± 0.96 g and 5.18 ± 0.34 cm, respectively, and temperature was maintained at 25 ± 1 ∞ C. Two replicate groups and two control groups of fish were applied among the four dietary treatments and each group consisted of 20 juvenile fish. Growth rate, feed efficiency and tissue lipid contents were not significantly affected ( P < 0.05) by CLA compared to the LA control group. A higher level of hepatosomatic index and lower growth rate were obtained from the CDHA dietary group. CLA and CDHA isomers were detected mainly in non-polar lipids of muscle, liver and brain. Lower values of mono-unsaturated fatty acids and 18:2n-6 levels were found in the CLA dietary fish group and there was no effect on the 20:4n-6 level in muscle, liver and brain. Conversely, higher levels of total mono-unsaturated fatty acids were found in liver and the 20:5n-3, 22:5n-3 level of the muscle polar fraction in the CDHA dietary fish group. These results indicate that 5% of CLA in diet does not influence the growth and feed efficiency of juvenile tilapia and that CLA was observed to be incorporated into muscle, liver and brain. Lower growth and higher liver lipid contents were observed in the CDHA-supplemented dietary fish group.

Effect of dietary conjugated linoleic acid (CLA) on growth performance, body composition and hepatic intermediary metabolism in juvenile yellow catfish Pelteobagrus fulvidraco

“…In respect of whole body composition, dietary CLA inclusion up to 2% did not significantly influence moisture and crude protein contents of whole body, in agreement with several studies with fish (Twibell et al, 2000(Twibell et al, , 2001Berge et al, 2004;Kennedy et al, 2005;Manning et al, 2006;Valente et al, 2007a,b). In the present study, dietary CLA reduced lipid content in whole body and liver, similar to those in hybrid striped bass and in yellow perch (Twibell et al, 2000(Twibell et al, , 2001, but in contrast with channel catfish, rainbow trout and Nile tilapia (Twibell and Wilson, 2003;Yasmin et al, 2004;FigueiredoSilva et al, 2005;Bandarra et al, 2006;dos Santos et al, 2010). The exact mechanism for the reduced fat accumulation by dietary CLA is not clear, but it is likely related to the inhibition of lipid absorption and lipogenesis and the promotion of lipid oxidation (Takahashi et al, 2003;Makol et al, 2009).…”

Deposição de ácido linoléico conjugado (CLA) em tilápias-do-nilo

“…Twibell et al (2000), em estudo realizado com híbrido de "striped bass" alimentado com 0,5 a 1,0% de CLA, também notaram aumento do 18:0 e diminuição do 18:1n-7 nos filés dos peixes. Yasmin et al (2004), estudando juvenis de tilápia-donilo alimentados com dieta com 5,0% de CLA, observaram diminuição do ácido linoléico (18:2n-6) e do total de n-3, do DHA (22: 6 n-3) e dos AGPI, assim como alterações nos níveis de ácido araquidônico (20:4 n-9) com o fornecimento de CLA, o que difere dos resultados obtidos nesse experimento para tilápia-do-nilo. A redução na concentração de AGMI observada por Yasmin et al (2004) está de acordo com os resultados encontrados por Twibell et al (2000).…”

“…Yasmin et al (2004), estudando juvenis de tilápia-donilo alimentados com dieta com 5,0% de CLA, observaram diminuição do ácido linoléico (18:2n-6) e do total de n-3, do DHA (22: 6 n-3) e dos AGPI, assim como alterações nos níveis de ácido araquidônico (20:4 n-9) com o fornecimento de CLA, o que difere dos resultados obtidos nesse experimento para tilápia-do-nilo. A redução na concentração de AGMI observada por Yasmin et al (2004) está de acordo com os resultados encontrados por Twibell et al (2000). Lee et al (1998) sugeriram que o isômero trans-10, cis-12 CLA reduz a relação AGPI por AGS, inibindo a atividade da enzima stearoyl-coenzima A dessaturase ( ∆ 9) no fígado, que cataliza a inserção de uma dupla ligação entre os átomos C9 e C10, tanto no 16:0 quanto no 18:0, para a formação do 16:1 (n-7) e 18:1 (n-9), respectivamente.…”

Influence of dietary conjugated linoleic acid on growth, fatty acid composition and hepatic lipogenesis in large yellow croaker (Pseudosciaena crocea R.)

“…Similarly, CLA does not seem to affect growth rate or feed conversion efficiency in Atlantic salmon fed with diets containing up to 4% CLA (Leaver et al, 2006). Higher levels of dietary CLA, up to 5% of diet, also had no effect on growth rate or feed conversion efficiency in juvenile tilapia (Oreochromis niloticus) (Yasmin et al, 2004). Twibell and Wilson (2003) observed that dietary CLA had little potential for improving growth responses in channel catfish.…”