Effects of dietary lipid source on reproductive performance and tissue lipid levels of Nile tilapia Oreochromis niloticus (Linnaeus) broodstock

Abstract

Summary Nile tilapia were fed diets supplemented with one of the following lipid sources at 5% level: cod liver oil, corn oil, soybean oil, a coconut oil‐based cooking oil or a combination of cod liver oil and corn oil (1 : 1). The control diet had no lipid supplement and tad fish meal as a sole protein source. A diet with soybean meal as a protein source was also tested. The number of females that spawned, spawning frequency, number of fry per spawning, and total fry production were increased at varying degrees by the supplemental lipid sources except for the cod liver oil. Fish fed the soybean oil diet tad the best overall reproductive performance over a 24‐week period. Fish fed the cod liver oil diet had the highest weight gain but the poorest reproductive performance. The suplemental lipids significantly increased crude fat levels in the liver and ovaries. Both males and females Ld the cod liver oil diet had the highest levels of fat in the liver and muscle. The ratio of total n‐6/n‐3 fatty acid in the liver, ovaries and testes was influenced by the supplemental lipid sources. It was highest in fish fed either the soybean oil diet, the corn oil diet, or the soybean meal diet and lowest in fish fed the control diet or the cod liver oil diet.

Effect of lipid feeding regimes and conditioning periods on gonads fatty acid profile and reproductive performance of the Nile tilapia (Oreochromis niloticus) broodstock

“…and SBO am /FO pm regimes reached 1.46, 1.25 and 1.38, respectively after two week of conditioning period. These ratios were consistent with the recommended ratios for Nile tilapia broodstock (1.4 and 1.9, respectively) as suggested by Santiago and Reyes (1993) and Ng and Wang (2011). With more accumulation of n-3 fatty acids under condition of sex separation and no spawning process, broods fed under the last feeding regimes for four weeks showed a decrease in ovaries ratio of n-6/n-3 to become 1.40, 0.75 and 0.93, respectively.…”

“…Same trend was observed after four weeks period. SBO-based diet revealed same trend in findings of Santiago and Reyes (1993) and Nandi et al (2001). Concerning linolenic acid (ALA), female broods delivered FO source in their diet in different forms (FO cont.…”

“…Tilapia broodstock have more needs for dietary n-6 HUFA than n-3 HUFA series and it was suggested that a balanced mixture between vegetable and fish oil sources is needed for optimal reproductive performance (Santiago and Reyes, 1993;El-Sayed et al, 2005;Hajizadeh et al, 2008;Ng and Wang, 2011). Upon our knowledge, no researcher work investigated the effect of time of the day on lipid sources and fatty acid utilization of tilapia broodfish.…”

“…Fish fed SBO am /FO pm diet had numerically higher GSI value than other treatments after 2wks subsequently after 4wks (Table 7). Santiago and Reyes (1993) who found that GSI of tilapia brood females did not significantly different among fish fed fish oil, soybean oil, coconut oil or corn oil diets. Ng and Wang (2011) found no significant differences regarding GSI values among tilapia broodstock fed vegetable oil based-diets (crude palm oil or crude palm oil + fish oil) and those fed fish oil diet.…”

“…Many authors suggested that vegetable oils or mixture of fish oil and vegetable oil resulted in better reproductive performance than fish oil solely. Santiago and Reyes (1993) reported that fish fed SBO diet had the best reproductive performance, while fish fed cod liver oil diet showed the poorest reproductive parameters. Ng and Wang (2011) found that tilapia broodstock fed crude palm oil-based diets (CPO or FO+CPO 1:1) showed the highest total eggs, higher spawning frequency and the best egg hatchability than broodstock fed FO or LSO diets this result may be due to the shorter inter spawning interval and higher spawning frequency.…”