Female Nile Tilapia Oreochromis Niloticus Research Articles

Reproductive performances of triploid male and female Nile tilapia Oreochromis niloticus (Linnaeus, 1758) at different ages

Abstract. Carman O, Mukti AT, Zairin JR M, Alimuddin. 2023. Reproductive performances of triploid male and female Nile tilapia Oreochromis niloticus (Linnaeus, 1758) at different ages. Biodiversitas 24: 4235-4242. Triploidization has been known as a chromosome set manipulation strategy to produce sterile fish. This study aimed to examine the reproductive and sterility performances of triploid male and female Nile tilapia Oreochromis niloticus (Linnaeus, 1758) at different ages. The triploidization process using heat shock of 41°C for four minutes at four Minutes After Fertilization (MAF) of the zygote old made the population of triploid tilapia. Two steps of fish rearing were conducted, namely indoor fish rearing and outdoor fish grow-out. Fish were reared in a controlled laboratory (indoor) at the Reproduction and Genetics Laboratory of Aquatic Organisms, Department of Aquaculture, Faculty of Fisheries and Marine Science, IPB University for four months, and then fish grow-out was performed in a controlled pond for two months. Reproductive performances such as Hepatosomatic Index (HSI), Gonadosomatic Index (GSI), gonadal development, and sterility of triploid and diploid for both male and female tilapias were analyzed. These results showed that triploid tilapia generally indicated late gonadal development and growth compared to diploids before and during maturation. Triploid female tilapia showed a lower HSI than diploid female tilapia (P<0.05). Otherwise, triploid and diploid males showed the same HSI. GSI of triploid males and females were lower than diploid males and females (P<0.05) at every age, namely three-, four-, five- and six-month-old fish. Based on the size and histology of the gonad, triploid male and female tilapias showed sterile characteristics with gametogenesis inhibition.

Evaluation of growth, sex (male proportion; sexual dimorphism), and color segregation in four cross combinations of different strains of XX female and YY male Nile Tilapia

AbstractFour cross combinations of different YY male and female Nile Tilapia Oreochromis niloticus strains were evaluated for growth, sex, and color segregation. Red color parental strains included blotched phenotypes. The Genetically Improved Farmed Tilapia (GIFT) was the only dark (wild‐type) color parental strain. Fish of the same age and cross were stocked in three replicate tanks for four crosses in one recirculating system for 167 days. Data recorded included feed consumed, body weight, total length, color, sex, and fillet weight. YY males crossed with GIFT females (Cross 2) exhibited superior growth that was significantly different (p < .05) to other three crosses. Male proportions were 79–100%. Only YY males crossed with the LSA female strain (Cross 4) yielded 100% males, but, Cross 4's productivity was inferior to that of Cross 2. Body weight advantage of males over females was 28.7–84.2%. Color segregation indicated that red color trait in Nile Tilapia is autosomal dominant, and black patch coverage was variable. This study showed that different parental strain combinations clearly impact productivity traits, and that YY male technology combined with crossbreeding provide the opportunity for genetic improvement and development of commercially beneficial superior traits in Nile Tilapia.

Reproductive performance of female Nile tilapia Oreochromis niloticus L. in South Kivu (DR Congo): comparison of two strains differing in origin and history of domestication

This study was conducted to evaluate the reproductive performance of females of Oreochromis niloticus originating from a strain of distant origin and extensively exploited in fish farming (Nyakabera strain) and a local strain recently removed from the natural environment (Lac Kivu strain). The experiment was carried out in triplicate with fry of 4.9 to 6.3 g placed in earthen ponds for a period of 6 months, at the Nyakabera fish station in South Kivu, Democratic Republic of Congo. The comparison of the two strains focused on the size of the first sexual maturity, gonado-somatic ratio, fecundity, egg diameter and condition factor. The results showed that under similar managed rearing conditions, the Nyakabera strain reaches sexual maturity earlier and is characterized by a higher gonado-somatic ratio and higher relative fertility, but a worse condition compared to the Lac Kivu strain. These differences, which indicate a better reproductive success of the Nyakabera strain, are related to the origin and the history of domestication, which are just as different from these two strains.

Neurokinin B-related Peptide Suppresses the Expression of GnRH I, Kiss2 and tac3 in the Brain of Mature Female Nile tilapia Oreochromis niloticus.

Neurokinin B (NKB) and neurokinin B related peptide (NKBRP) belong to tachykinin peptide family. Theyact as a neurotransmitter and/or neuromodulator. Mutation of NKB and/or its cognate receptor, NK3R resulted in hypogonadotropic hypogonadism in mammals, implying a strong involvement of NKB/NK3R system in controlling mammalian reproduction. Teleosts possess NKBRP as well as NKB, but their roles in fish reproduction need to be clarified. In this study, NKB and NKBRP coding gene (tac3) was cloned from Nile tilapia and sequenced. Based on the sequence, Nile tilapia NKB and NKBRP peptide were synthesized and their biological potencies were tested in vitro pituitary culture. The synthetic NKBRP showed direct inhibitory effect on the expression of GTH subunits at the pituitary level. This inhibitory effect was confirmed in vivo by means of intraperitoneal (ip) injection of synthetic NKB and NKBRP to mature female tilapia (20 pmol/g body weight [BW]). Both NKB and NKBRP had no effect on the plasma level of sex steroids, E2 and 11-KT. However, NKBRP caused declines of expression level of GnRH I, Kiss2 and tac3 mRNAs in the brain while NKB seemed to have no distinct effect. These results indicate some inhibitory roles of NKBRP in reproduction of mature female Nile tilapia, although their exact functions are not clear at the moment.

Reproductive biology of female Nile tilapia Oreochromis niloticus (Linnaeus) reared in monoculture and polyculture with African sharptooth catfish Clarias gariepinus (Burchell).

This study was conducted to assess the reproductive biology and early breeding behaviour of female Oreochromis niloticus reared in monoculture and polyculture with Clarias gariepinus in earthen ponds for 8 months. Results revealed no significant difference in length at first maturity (L50) between females reared in monoculture and polyculture systems. Similarly, no significant differences were detected in absolute fecundity, relative fecundity, gonado-somatic index and condition factor between the two culture systems. The absolute fecundity was more strongly correlated with total length and body weight than with ovary weight. The study concluded that early breeding of O. niloticus in captivity is not affected by the culture systems used. Therefore, O. niloticus production in either system can be improved only through proper pond management techniques.

Cloning of brain aromatase gene and expression of brain and ovarian aromatase genes during sexual differentiation in genetic male and female Nile tilapia Oreochromis niloticus.

A brain aromatase gene was identified from the Nile tilapia Oreochromis niloticus. The cDNA sequence of this gene differed from that of the ovarian aromatase gene previously reported from this species. Tissue specific expression for both brain and ovarian aromatase genes was examined in the tissues of adult tilapia. Brain aromatase mRNA was expressed in the brain, kidney, eye, ovary, and testis, but not in the liver and spleen. Ovarian aromatase mRNA was expressed in the brain, spleen, ovary, and testis but not in the eye, kidney, and liver. Differential aromatase gene expression between the sexes was investigated in all-male (XY) and all-female (XX) groups of tilapia fry from fertilisation throughout the sexual differentiation period. Semi-quantitative RT-PCR analysis revealed that the initiation of expression of both aromatase genes lay between 3 and 4 dpf (days post fertilisation) in both sexes. The level of brain aromatase mRNA gradually increased throughout the period studied with little difference between the sexes. This contrasted with marked sexual dimorphism of ovarian aromatase mRNA expression. In females, the expression level was maintained or increased gradually throughout ontogeny, while the level in males was dramatically down-regulated between 15 and 27 dpf. Subsequently, the level of ovarian aromatase mRNA expression fluctuated slightly in both sexes, with the expression in females always being higher than in males. These findings clearly suggest that ovarian aromatase plays a decisive role in sexual differentiation in this species and that this is achieved by down-regulation of the expression of this gene in males. Mol. Reprod. Dev. 59: 359-370, 2001.

Both n-6 and n-3 Fatty Acids Are Required for Maximal Growth of Juvenile Hybrid Tilapia

An 8-week feeding experiment was conducted to provide preliminary information on essential fatty acid requirements of hybrid tilapia (female Nile tilapia Oreochromis niloticus × male blue tilapia O. aureus). Seven semipurified diets containing 30% crude protein from casein with 3.2 kcal available energy/g were supplemented with 5% of either lard (L), corn oil (C), cod liver oil (F), lard and corn oil (1:1, L–C), lard and cod liver oil (1:1, L–F), corn oil and cod liver oil (1:1, C–F), or lard, corn oil, and cod liver oil (1:1:1, L–C–F). Each diet was fed to three replicate groups of fish initially weighing 0.84 ± 0.02 g (mean ± SD) in 60-L aquaria connected as a closed recirculating-water system containing freshwater at 25 ± 1°C. Results indicate that significantly (P < 0.05) higher weight gain, feed efficiency (FE), protein efficiency ratio (PER), and protein deposition (PD) were associated with fish fed the diet supplemented with F. Among groups fed diets containing F, weight gain was significantly higher in fish fed L–C–F than in fish fed L–F and F. Fish fed L–C–F had significantly higher FE and PER values than those fed F, L–F or C–F. Protein deposition was significantly better in fish fed L–C–F than in fish fed L–F. Fatty acid compositions of liver and muscle in fish generally reflected the composition of the diet. These data suggest that n-3 highly unsaturated fatty acid as well as n-6 fatty acid are essential for maximum growth of juvenile hybrid tilapia.