EFFECT OF ALBINO GENE ON INTRASPECIFIC HYBRIDIZATION OF NORMAL AND ALBINO AFRICAN CATFISH (Clarias gariepinus)

Abstract

The effect of albino gene on intraspecific hybridazation of African Catfish and Albino Clarias gariepinus was carriedout to determined their latency period, fecundity, fertility, hatchability survival, growth performance, some morphometric and meristics characteristics and genetic characterization of parents and offspring of F1 generation. A total of four (4) mating combination experiments were conducted using eight (8) ripped, matured normal and albino Clarias gariepinus with average body weight of 1.64kg. The broodstock were purchased from Abdulfana fish farm Yola and transported in 50 litres jerican to the Department of Fisheries and Aquaculture Adamawa State University Mubi. They were acclimatised for 10 days, vital feed were fed daily at 5% of their biomass. Artificial breeding was cariedout using Ovaprim hormone at a dose of 0.50ml/kg and 0.25ml/kg for female and male respectively. After hand stripping of the female brooders, nine hundred and sixty (960) eggs were used for fertilization in each mating combination, 320 eggs replicated three times using Randomized Complete Design (RCD) to determine the percentage Fertility and Hatchability of the eggs. Two hundred and forty fry of two weeks old from each treatment were randomly selected and stocked in same culture system and fed with Coppens feed at 10% body weight, the experiment lasted for the period of 18 months for both F1 ans F2 gerations, where weight, length and survival/mortality rate, in each treatment and replications were recorded weekly.Water quality parameters were monitored weekly. Gene characterization (DNA extraction, Electrophoresis, Selection of Microsatellite Markers, Polymerase Chain Reaction (PCR) Amplifications and Electrophoresis for PCR, was carried out on the parent stock and all the offspring of mating combination in F1 generation. It was observed that female albino Clarias gariepinus had the highest latency period of 13.50±0.22 hours at 27.50±0.20oC and less fecundity of 4032±0.12, while the normal Clarias gariepinus had the least latency period of 12.00±0.21 hours and high fecundity of 7020±0.23 at similar temperature. Similarly crossed between NN♂ x NN♀ had the highest fertility and hatchability of 44.79±0.32% and 72.6±0.24%, while the least value of 27.92±0.31% and 46.3±0.43% were recorded in AA♂ x NN♀. Also crossed between NN♂ x AA♀ had the highest final mean weight gain of 912.90 ±0.00g, followed by NN♂ x NN♀ with 900.75 ±0.00g, while NN♀ x AA♂ and AA♂ x AA♀ had the least value of 893.88±0.00g and 852.98±0.00g respectively. High survival rate of 41.25±0.00% was recorded in crossed between AA♂ x AA♀, while NN♂ x AA♀ had the least value of 12.50±0.00%. The Head width, eye diameter and occipital fontanelle of the F1 generation was higher than that of the parents. All the water quality parameters measured during the course of the research were within the normal range for tropical catfish cultured. The two loci of normal Clarias gariepinus (Cg01) and albino Clarias gariepinus (Cg02) showed amplification. The size of the two (2) microsatellite loci ranged from 0.92 to 1680 bp, with low estimates of null allele frequencies across all populations for the parent stock and 0.93 to 1.00 for F1 generation. The number of Allele observed from the genetic analysis of parent stock and F1 generation of Cg01 showed heterozygosity and the second allele on the second band Cg02 shows homozygosity. However, a homozygote excess was estimated in the parents of Cg02 and the result was 100% in both the parent and F1 generation of the normal and albino Clarias gariepinus. Normal male and female Albino Clarias gariepinus can be use by fish farmers to produced hybrid that have high survival rate and can grow faster. Further study should be carriedout to determined the causes of had skin, large head width, large eye diameter and wide occipital fontanelle of the F1 generation.