The feed provided to breeding fish is one of the main factors influencing the quality of fish gametes. This study was carried out to evaluate the influence of ascorbic acid on growth, haematological parameters and sperm quality of Lebranche mullet males (Mugil liza). Six diets with different levels of ascorbic acid (0; 53; 107; 216; 482 and 708 mg/kg) were tested in triplicate for 75 days. During spermiation (first gonadal maturation), 144 individuals (205.7 ± 11.5 g and 25.7 ± 0.4 cm) were randomly distributed in 18 experimental tanks. Growth parameters were evaluated at the beginning and end of the experiment. Fish blood was collected to analyse glucose, total protein and erythrocyte count (EC) (n = 9). Fish (n = 12) from each treatment were euthanized to determine hepatosomatic index (HSI) and gonadosomatic index (GSI). Semen was collected to evaluate spermatic density, cell membrane integrity and sperm motility. No difference (p > .05) was found on growth parameters, GSI, HSI and total protein. However, EC was lower in fish fed without ascorbic acid (the control group). Ascorbic acid supplementation provided positive effects on sperm characteristics. Fish from treatments with 53 and 107 mg/kg presented the best results for motility time (133.30 ± 4.25 and 135.00 ± 2.77 respectively). Treatments with 107, 216 and 708 mg/kg provided the best results for motility rate (92.0 ± 2.9%, 93.0 ± 5.8% and 93.0 ± 5.8% respectively). Supplementation with 107 and 216 mg/kg provided the best results for plasma membrane integrity (70.12 ± 9.10% and 76.3 ± 3.1% respectively). Lower spermatic density was observed in fish without ascorbic acid supplementation, although no difference was found in sperm density among the treatments with ascorbic acid (p < .05). Considering these results, supplementation of dietary ascorbic acid between 107 and 216 mg/kg optimizes the spermatic quality in males of lebranche mullet.

Temperature is a limiting factor to the development of fish eggs and larvae. The aim of this study was to define the optimal temperature for egg incubation, larval survival and development of Sardinella brasiliensis larvae. Eggs were obtained by natural spawn and collected after the blastopore enclosure. Fertilized eggs were incubated at 17, 20, 23, 26 29 or 32°C in beakers. Larval development (200 eggs L−1), hatching and survival rates (100 eggs L−1) and RNA/DNA ratio were evaluated. The best temperature for hatching was 28°C, the best survival rate was obtained at 24.7°C, and 100% of the larvae died at 18.4°C. The time of mouth opening (24 to 51 h) and moment of eye pigmentation (24 to 45 h) varied with temperature. No significant difference was found in the RNA/DNA ratio between the treatments, indicating the nutritional status of the larvae. The interval between 24.7 and 28°C resulted in a better hatching rate and larval survival. Water temperature affected the hatching rate, survival and morphometric development of S. brasiliensis larvae.

The Lebranche mullet (Mugil liza Valencienne, 1836) species is of great importance to artisanal and industrial fishing on the Atlantic coast of South America. In Brazil, it is the seventh most captured fish species, especially due to the rise in the export interest for the fish roe, known as the "Brazilian caviar" (Ferreira et al., 2011). However, artisanal fishing has been decreasing in the last 30 years, while industrial fishing has increased (MPA; MMA, 2015). Due to overfishing in recent years, the mullet was categorized as "near threatened" by the International Union for Conservation of Nature (IUCN) (MPA; MMA, 2015). A management plan for the sustainable use of this species was developed by the Brazilian government, considering its importance and vulnerability in Brazil's South and Southeast regions (IBAMA 2007). In this context, the need arises to establish successful cultivation procedures for this species.The Lebranche mullet has a variety of characteristics that facilitate its commercial rearing, such as high adaptability to wide temperature and salinity ranges, and acceptance of artificial diets (Carvalho et al., 2019). Temperature is one of the most important environmental variables. It can affect not only ontogeny during the first larval stages, but also the metabolism, oxygen consumption, growth, weight, yolk sac and body size of the marine organisms (Imsland et al., 2019;Jian et al., 2003;Neelmani et al., 2019). An increase in temperature can accelerate larvae development and change morphological characteristics, such as development of the pectoral fin, mouth opening and eye pigmentation (Fukuhara, 1990;Green & Brown, 2013).Weight and standard length are often used to evaluate larvae growth rate. However, other methods such as protein content, amount of energy amount and nucleic acid analysis (RNA/DNA ratio) can provide more accurate data (Buckley et al., 2008;Perez-Dominguez & Dahm, 2011). The RNA/DNA ratio has been accepted