Quantitative analysis of black blotching in a crossbred red tilapia and its effects on performance traits via a path analysis methodology
Red tilapia is a phenotype with potential value to the tilapia industry due to its attractive skin coloration. However, the presence of black blotches scattered on the body makes these fish less valuable than blemish-free red fish. The correlation between the degree of blotching and other economic traits is important for selective breeding programs including high-performance red fish without black blotches. Therefore, this study aimed to assess the magnitude and direct and indirect effects of blotching in crossbred red tilapia on the growth rate and body measure traits using path analysis methodology. Six genetic groups were evaluated in terms of body measurements, body weight rate, and proportion of black blotching over 250 days of growth: Chitralada and Red-Stirling; crossbred F1—♀ Red-Stirling × ♂ Chitralada and ♀ Chitralada × ♂ Red-Stirling, and the introgressive crossbreeding—♀ CR × ♂ Chitralada and ♀ Chitralada × ♂ CR (C × CR). All variables showed high and positive linear correlations. Individuals with black blotches had lower coefficients of correlation with other variables (body weight and measurements); the direct and indirect effects are near zero. The path analysis indicated a lack of genetic correlation between the degree of black blotches and the economic traits of red tilapia. This facilitates the development of high growth performance red fish with blotched-free reddish skin.
KeywordsAquaculture Red tilapia Pigmentation Growth Breeding program Oreochromis niloticus
The authors are deeply indebted to Mr. Adilson Feliciano Duarte and all the staff of Indústria Brasileira do Peixe Ltda for their assistance during the work field. Also, Dr. Philip C. Scott for his help during the image processing stage. This work was developed as part of the full requirements for the Doctoral dissertation in Animal Sciences at the Federal University of Lavras (UFLA). AWSH and RTFF are recipients of CNPq productivity scholarship.
AAL designed the study, conducted the fieldwork, and managed the data collection. RVRN revised the manuscript and interpreted the results. TTR performed the statistical analysis. MCSR performed the image analysis. RTFF designed the study and revised the manuscript. AWSH supervised the project, wrote the manuscript, and approved the final manuscript.
This study was funded by the São Paulo Research Foundation (FAPESP #11/23752-2) and the authors thank CNPq and Minas Gerais Research Foundation for funding Aline scholarship (141583/2011-8 and BDP206-14 respectively).
Compliance with ethical standards
All applicable international, national, and/or institutional guidelines for the care and use of animals were followed. The approval’s register of the Ethics Committee on the Use of Animal at the University of Mogi das Cruzes is 003/2013.
Conflict of interest
The authors declare that they have no conflict of interest.
Informed consent was obtained from all individual participants included in the study.
- Balarin JD, Hatton JP (1979) Tilapia: a guide to their biology and culture in Africa. Pisces Press, University of Stirling, Scotland, 1979Google Scholar
- Box GEP, Cox DR (1964) An analysis of transformations. J R Stat Soc 26:211–252Google Scholar
- Carvalho SP, Cruz CD (1996) Diagnosis of multicollinearity: assessment of the condition of correlation matrices used in genetic studies. Braz J Genet 19:479–484Google Scholar
- Castillo-Campo LF (2012) Tilapia roja 2011: Una evolución de 29 años, de la incertidumbre al éxito. Editorial Académica Española, SpainGoogle Scholar
- Epskamp, Stuber (2017) Path diagrams and visual analysis of various SEM packages’ output. R Package Version 1:1 Available at: https://cran.r-project.org/web/packages/semPlot/semPlot.pdf Google Scholar
- Ferreira EB, Cavalcanti PP, Nogueira DA. (2017) ExpDes: experimental design package. R package Version 1.2.0. Available at https://cran.r-project.org/web/packages/ExpDes.pt/ExpDes.pt.pdf
- Galman OR, Avtalion RR (1983) A preliminary investigation of the characteristics of red tilapias from the Philippines and Taiwan. In: Fishelson L, Yaron (eds) Proceedings of the International Symposium on Tilapia in Aquaculture. Tel-Aviv Univ. Press, Tel-Aviv, pp 291–301Google Scholar
- Galman OR, Moreau J, Avtalion RR (1988) Breeding characteristics and growth performances of Philippine red tilapia. In: Pullin RSV, Bhukasawan T, Tonguthai KT, McLean JL (eds) The Second International Symposium on Tilapia in Aquaculture, ICLARM Conference Proceedings 15, Bangkok, Thailand, and International Center for Living Aquatic Resources Management, Manila, Philippines, pp.169–175Google Scholar
- Hussain MG (1994) Genetics of body color inheritance in Thai and Egyptian red tilapia strains. Asian Fish Sci 7(Suppl. 4):215–224Google Scholar
- Koren A, Pruginin Y, Hulata G (1994) Evaluation of some red tilapia strains for aquaculture: I. Color inheritance. Isr J Aquac Bamidgeh 46:9–12Google Scholar
- Kuo H (1979) Notes on the development of red tilapia in Taiwan. Fish Mag 26:35–38Google Scholar
- Kuo H, Tasy TT (1984) The characteristic variation of red tilapia. Bull Taiwan Fish Res Inst 36:55–67Google Scholar
- Mires D (1988) The inheritance of black pigmentation in two African strains of Oreochromis niloticus. In: Pullin RSV, Bhukasawan T, Tonguthai KT, McLean JL (eds) The Second International Symposium on Tilapia in Aquaculture, ICLARM Conference Proceedings 15, Bangkok, Thailand, and International Center for Living Aquatic Resources Management, Manila, Philippines, pp. 237–241Google Scholar
- Rahman SA, Zambry H, Basha S, Kamarzaman S, Chowdhury AJ (2013) The potential role of red tilapia (Oreochromis niloticus) scales: allergic reaction test in mice. J Appl Pharm Sci 3:45–50Google Scholar
- Rajaee AH (2011) Genetic approaches to the analysis of body colouration in Nile tilapia (Oreochromis niloticus). PhD Thesis. University of Stirling, Scotland, UKGoogle Scholar
- Thodesen J, Rye M, Wang YX, Yang KS, Bentsen HB, Gjedrem T (2011) Genetic improvement of tilapias in China: genetic parameters and selection responses in growth of Nile tilapia (Oreochromis niloticus) after six generations of multi-trait selection for growth and fillet yield. Aquaculture 322:51–64CrossRefGoogle Scholar
- Thodesen J, Rye M, Wang YX, Li SJ, Bentsen HB, Yazdi MH, Gjedrem T (2013) Genetic improvement of tilapias in China: genetic parameters and selection responses in growth, survival and external color traits of red tilapia (Oreochromis spp.) after four generations of multi-trait selection. Aquaculture 416:354–366CrossRefGoogle Scholar
- Weisberg S, Fox J (2011) An R companion to applied regression, 2nd edn. Sage, Thousand OaksGoogle Scholar