Indoor evaluation of anti-fertility effect of papaya (Carica papaya L.) leaf and seed in controlling prolific breeding of Nile tilapia (Oreochromis niloticus: Cichlidae)

Abstract

Nile tilapia has been spread to all continents as an aquaculture fish due to its desirable qualities of a culture species. However, its precocious spawning is a global bottleneck with this species. A 90-days experiment was conducted to determine antifertility effect of Papaya seed powder (PSP) and papaya leaf powder (PLP) powders on Nile tilapia. The experiment was carried out in eight tanks grouped in to three treatments (T1, T2 & T3) and one control, each in duplicates. The treatments consisted of mixtures of PSP and PLP combined in different proportions as 1.5g PLP and 0.5g PSP in T1, 1.5g PSP and 0.5g PLP in T2 and 1g PSP and 1g PLP in T3 to 1 kg of basal diet. Fishes in the control tanks were provided only with the basal diet. The fishes were fed at 10 % of their body weight throughout the experimental period. One-way ANOVA was used to test the differences in the mean body weight, body length and gonad weight among the control and three treatment groups. For male highest gonad weight (0.22 ± 0.16 g) and GSI (0.79 ± 0.38) were recorded in control groups. Least values of gonad weight (0.03 ± 0.02 g) and GSI (0.11 ± 0.10) for male were recorded in T3. For the females, the highest gonad weight (0.27 ± 0.25g) and GSI (0.84 ± 0.80) were also recorded in control group, while the least values of gonad weight (0.17 ± 0.21g) and GSI (0.43 ± 0.54g) were recorded in T3 and thus maximum sterilizing effects, were recorded in T3 that consisted of equal proportions of the seed and leave powders. Gonad development was ranges II –IV in control groups and impaired in all treatments in both male and female fishes. Fishes in T3 had best food conversion rate (FCR) (0.91 to 1.80), whereas least food conversion rate (FCF) was recorded for fishes in control group (1.02 to 1.90). Maximum survival rate (55%) was recorded for fish in T3, whereas minimum survival rate (40%) recorded for fish in T2 and the survival rate of fish in control group was 45%.The growth performance (i.e. mean weight and length) of fish in all treatments and control group showed no significant differences (P>0.05).Reproductive parameters showed clearly that PSP and PLP induce sterility in Nile tilapia in both male and female. Both mixture of PSP and PLP at dosage of (1g of PSP and 1g of PLP) incorporated to 1kg of basal diet be used by farmers to control undesirable breeding of Nile tilapia.