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This study was conducted at the fish farm & the fish lab in the Fish Branch of the Department of Animal Production, Faculty of Agriculture, Ain Shams University, Egypt.
The study included two experiments:
The first experiment:
The aim of this experiment was to study the development of the sexual glands of different stages of the mono sex (all male) Nile tilapia fish (16.33 ± 0.71 g/fish), as well as the growth and chemical analysis of the fish body for 16 weeks. The experiment was carried out in a fish production pond made of cement (27 m × 13.5 m × Depth 1.5 meters). A random sample (10 fish) was taken every 14 days. The weight of the fish was calculated to adjust the feeding ratios and calculate the growth parameters. The histological examination of the gonads was performed every two weeks to track their growth and development. The experiment lasted 16 weeks. Fish were fed on a commercial diet (30% crude protein) at 3% of their total biomass.
This study was designed to evaluate the effect of replacing fishmeal at different levels of soybean meal. The aim of the second experiment was to study the effect of different levels of soybean on production performance and development of sexual glands, as well as follow-up of both growth and chemical analysis of the fish body. In this study, Proportion of protein and equal in energy. Mixed sex Nile tilapia (2.36 ± 0.26 g/fish) were fed 4 different diets at a rate of 3% of total biomass.
The experiment was conducted in 12 fiberglass basins (60 x 50 x 60 cm), representing four treatments in each treatment. Three replicates with a stocking of 20 fish / basin with average weight (2.36 ± 0.26 g).
The fish were fed on a standard diet containing 30% protein and four different levels of soybean were added as follows: 20, 30, 40 and 50% in diet 1, 2, 3 and 4, respectively.
The results are summarized in the following:
The results showed a relationship between fish growth and the development of gonads during different age periods throughout the production cycle. The results showed that sexually tilted tilapia males could double their weight every 4 weeks. The histological study also showed that males started the process of forming sperm at a body weight of 29,16 g. During this age, the histological sectors of the test showed deterioration and apparent decay in the microbial tissue units. Despite this deterioration, by increasing weight and age, the growth and development of sperm cells continued. Later, the histological sectors showed that the testicles began to recover their normal composition when the fish reached 4 - 5 months of 54.66 - 68.33 (g / fish). At the age of 5.5-6 months, the fish regained the natural structure of their testicles completely. This was evident from the cohesion of the testis and the presence of all types of germ cells and the emergence of sperm stored heavily in the testicular cavity and testicular channels, confirming the arrival of males to sexual maturity. Based on the results obtained, a relationship between age, body weight, and the growth and development of sexual genders can be inferred. And that the hormonal treatment of tilapia seeds in the early stages of the production of tilapia (all males) leads to a significant deterioration in the structure of the testis continues until the fish begin to enter puberty, after which males can overcome this deterioration and restore the natural structure of the test and achieve full sexual maturity at Ranging from 5.5 to 6 months.
The results showed that soybeans can be used as an alternative to fishmeal as a protein source. The results have been showed that male tilapia males could double their weight every 4 weeks. The results showed that when using soybean meal at different levels, no significant differences were found between the different parameters and some in the growth parameters (final weight, weight increase, daily growth rate, growth rate, food conversion rate), rations, Productivity value for PPV protein.
The results showed significant differences in the body content of fish, protein, fat and ash. The protein values ranged from 63.12 to 68.74%, fat ranged from 15.73 to 17.08%, total moisture (79.6 to 80.37%) and ash from 10.9 to 11.79%). The histological examination of sexual glands in males (testis) and in females (ovaries) showed the result of histological examination in male tilapia species with increased percentage of replacement of soybean fish powder on estrogen similarities. The results showed that treatment 1, treatment 2 But the results showed that by increasing the replacement ratio of 30% soybean meal as an alternative to fish meal, treatment 3, treated 4 was affected. The results showed deterioration in testicular growth and development. The result of the histological examination in the Nile tilapia females in early ages was that the ovaries increased to increase growth and development in the oocytes. However, in the older ages, the results showed that despite the increased replacement, the ovulation process was faster, but the replacement rate increased by 30% Soybean meal showed a decrease in the number of oocytes.