Growth performance, reproductive status, and chromosomal instability in triploid Nile tilapias.

Reproductive control is one of the biggest challenges in tilapia production and triploidy was developed as an alternative to sterilization. In general, polyploids present chromosomal instability but for triploid Nile tilapia it has yet to be reported. This study evaluated the chromosomal instability from juveniles to adulthood, growth performance and gonadal status of tilapia hatched from eggs submitted or not to heat shock for triploid induction. Nile tilapia oocytes were fertilized (1,476 oocytes), half of the eggs were subjected to a four-minute shock in 41 °C water four minutes after fertilization and the other half were not (Control group). The eggs were incubated (at 27°C) and 160 larvae from the treated group hatched and survived after yolk sac absorption. The determination of ploidy was performed by flow cytometry at 85th (juveniles) and 301st (adults) days of age post yolk sac absorption. At the time of the first cytometry analysis there were 73 surviving juveniles from the treated group, and only 14 were confirmed triploid. However, at the analysis of adult ploidy, one out of 8 surviving adult tilapias from the 14 confirmed triploid juveniles remained triploid. Gonadal histology showed that the non-remaining triploids continued to produce gametes. The growth performance of triploid tilapia was initially superior to that of diploid tilapia during the juvenile phase, but similar in adults. Once the chromosome sets are lost and the tilapias become diploid again, at least in tissues with a high proliferation rate, such as the hematopoietic tissue that was analyzed (and possibly in gonads), all possible advantages of triploids are probably lost. Thus, our results suggest that, due to genomic instabilities, the triploid generation of tilapia has low efficiency.

Skeletal muscle mass increases after viral eradication with direct-acting antivirals in patients with chronic hepatitis C: A longitudinal study.

BACKGROUND: Results of studies evaluating the effect of viral eradication following direct-acting antiviral (DDA) therapy on skeletal muscle mass of patients with chronic hepatitis C (CHC) are scarce. AIM: To assess the components of sarcopenia (low muscle mass, low muscle strength and low physical performance) in a cohort of CHC individuals before and after DAA therapy. METHODS: We performed a longitudinal study of patients with CHC who underwent body composition assessment before (T0), and at 12 (T1) and 48 (T2) weeks after DDA therapy. Bioelectrical Impedance Analysis was used to assess skeletal mass muscle (SM) and phase angle (PhA). SM index (SMI) was calculated by dividing the SM by squared height. Muscle function was evaluated by hand grip strength (HGS) and timed up-and-go (TUG) test. Mixed-effects linear regression models were fitted to SMI, HGS and physical performance and were used to test the effect of HCV eradication by DAA. RESULTS: 62 outpatients (mean age, 58.6 ± 10.8 years; 58% with compensated cirrhosis) were included. Significant decreases in liver fibrosis markers and an increase of 0.20 and 0.22 kg/m2 in the SMI were observed at T1 and T2. Following DAA therapy, an increase of one unit of PhA was associated with a reduction of 0.38 min in TUG. CONCLUSION: HCV eradication with DAA therapy was associated with a dynamic reduction of non-invasive markers of liver fibrosis and increased muscle mass in 62 patients with CHC who had an undetectable HCV load at 12 weeks after completion of antiviral treatment.

Effects of different temperatures on testis structure and function, with emphasis on somatic cells, in sexually mature Nile tilapias (Oreochromis niloticus).

The Nile tilapia (Oreochromis niloticus) is economically one of the most important freshwater fish and is an excellent model for studies under laboratory conditions. Temperature is considered a very important modulator of reproductive activity in fish, although few studies have specifically addressed the effects of this key factor on morphological and functional aspects of teleost testes. Therefore, our main objectives in the present study were to analyze the effects of different temperatures (20, 25, 30, and 35 degrees C) on testicular somatic and germ cells in sexually mature Nile tilapias. Compared with fish kept at other temperatures, tilapias maintained at 20 degrees C demonstrated increased (P < 0.05) Sertoli cell and Leydig cell proliferation, volume density and frequency of most type B spermatogonia, and germ cell apoptosis. Conversely, tubular fluid secretion was decreased (P < 0.05) in the same animals. Although not significant, type A spermatogonia proliferation followed the pattern established for Sertoli cell and Leydig cell mitotic activity, suggesting that they preferentially would proliferate at lower temperatures. Based on most results found in our study and considering that tilapias are nonseasonal breeders, we suggest a model for temperature action on tilapia testes in which lower temperature (20 degrees C) would favor type A spermatogonial renewal, Sertoli cell and Leydig cell proliferation, and germ cell apoptosis, whereas higher temperatures (30-35 degrees C) would trigger rapid germ cell differentiation. Thus, tilapias could potentially be utilized in studies involving hormones and factors related to Sertoli cell and Leydig cell proliferation and spermatogonial self-renewal or differentiation.