Abstract Continuous illumination and increased feeding periods have enhanced growth in commercial fish species. However, oxygen consumption under these conditions has yet to be previously assessed in agastric short-intestine fish. This study evaluated Chirostoma estor (Atherinopsidae) oxygen consumption under three specific feeding and light regimes: resting-unfed, routine-fed, and continuous light/feeding. Fish in the continuous light/feeding condition presented oxygen consumption levels 60 and 20% higher than resting-unfed and routine-fed fish, respectively. The latter implies that constant high oxygen supply levels are required to satisfy the demand for C. estor raised under these high growth rate conditions. The present study shows the relevance of determining oxygen consumption levels during continuous illumination and extended feeding periods to consider optimal oxygen levels required to achieve better performance indicators, such as the growth and welfare of atherinopsids and species with similar digestive configurations.

Resumen La iluminación continua y el aumento de frecuencias alimenticias han mejorado el crecimiento de peces en cultivo. Sin embargo, el consumo de oxígeno en estas condiciones no se ha evaluado en peces agástricos de intestino corto. Este estudio evaluó el consumo de oxígeno de Chirostoma estor bajo tres regímenes específicos de alimentación y luz: reposo sin alimentación, alimentación de rutina y alimentación/luz continua. En este último tratamiento los peces presentaron niveles de consumo de oxígeno de 60 y 20% más altos que los peces en reposo y con alimentación rutinaria, respectivamente. Esto implica que se requieren niveles elevados y constantes de suministro de oxígeno para satisfacer la demanda de C. estor en cultivo en condiciones crecimiento acelerado. El presente estudio muestra la relevancia de determinar los niveles de consumo de oxígeno bajo protocolos de crecimiento acelerado para lograr mejores indicadores de desempeño de otras especies con configuraciones digestivas similares.

ABSTRACT A feeding trial was performed to assess dietary protein:lipid ratios for the grow-out phase of the bullfrog (Lithobates catesbeianus). Nine balanced isoenergetic diets were formulated, combining three different protein levels (300, 400, and 500 g kg−1) with three different lipid levels (50, 100, and 200 g kg−1), designated as P300/50L, P300/100L, P300/200L, P400/50L, P400/100L, P400/200L, P500/50L, P500/100L, and P500/200L. Additionally, a commercial fish feed, commonly used in Mexico to feed bullfrogs, was also tested during the experiment. Growth performance, animal performance parameters, carcass composition, and fatty acid profiles in muscle and liver were evaluated. The feeding trial results showed that all the experimental diets enhanced growth, feed conversion ratio, and frog-leg weight compared with the commercial diet. Bullfrogs had higher growth with 400 and 500 g kg−1 of dietary protein regardless of dietary lipid content. It was also notable that with the P500/200L diet, frogs doubled the weight of those fed the commercial diet. DHA, EPA, and total omega-3 fatty acids were double in muscle and two to eight times higher in the liver compared with the commercial diet. In all cases, the final proximal composition of carcass reflected the diet composition. It is suggested that a diet containing 400 g kg−1 of protein and 50 g kg−1 lipids (protein/lipid ratio: 7.4; gross energy: 18.2 MJ kg−1) is adequate for bullfrog performance during the grow-out phase to achieve market size in a shorter period, thus, reducing farming risks and production costs. proteinlipid growout grow out Lithobates catesbeianus. catesbeianus . catesbeianus) formulated 300, 300 (300 kg1 kg 1 50, (50 100 20 kg−1, , P30050L PL P300 50L P L P300/50L P300100L 100L P300/100L P300200L 200L P300/200L P40050L P400 P400/50L P400100L P400/100L P400200L P400/200L P50050L P500 P500/50L P500100L P500/100L P500200L Additionally bullfrogs experiment parameters evaluated ratio frogleg frog leg 40 kg− content DHA EPA omega3 omega 3 omega- cases 5 protein/lipid 7.4 74 7 4 energy 182 18 2 18. period thus costs 30 (30 (5 10 P30 P40 P50 7. (3 ( P3 P4 P5

ABSTRACT The nutritional quality of tilapia fillet is characterized by low omega-3 polyunsaturated fatty acids (n-3 PUFAs). The objective of the present study was to evaluate the effect of different dietary concentrations of chia (Salvia hispanica) and flaxseed (Linum usitatissimum) meal on the omega-3 fatty acid content of tilapia (Oreochromis niloticus) fillet. Six experimental diets incorporating 5, 10, and 15% chia or flaxseed meals, respectively, were given to the fish (238.36 ± 7.61 g, initial weight) for 45 days before harvesting. The α-linolenic acid (ALA) and n-3 PUFA contents in the fillet differed significantly among diets (P < 0.05). Diets containing 15% chia or flaxseed meal had the highest concentrations of ALA (4.80 and 4.75%, respectively) and n-3 PUFA (13.65 and 15.92%, respectively). Thus, chia or flaxseed meal dietary inclusion increased the ALA and n-3 PUFA contents in the tilapia fillet. Chia or flaxseed meals are useful and potential alternatives to improve the nutritional value of O. niloticus fillets.

RESUMO O ácido docosahexaenóico (DHA) é o ácido graxo ômega-3 mais importante e menos disponível na dieta humana ocidental. Atualmente, a fonte de ácidos graxos poliinsaturados de cadeia longa ômega-3 (LC-PUFA) depende principalmente da pesca extrativista, tornando esse recurso insustentável em um futuro próximo. Nos últimos anos, uma alta taxa de biossíntese e acúmulo de DHA foi descoberta em uma espécie de água doce (Chirostoma estor) pertencente à família Atherinopsidae. Deste modo, surgiu o interesse em avaliar a composição de ácidos graxos em outros membros da família. Portanto, este estudo compila dados originais da composição de carne de oito espécies de aterinopsídeos de ambientes de água doce e salobra, selvagens ou cultivadas. Altos níveis de DHA (16 a 31%) foram encontrados em todos os membros da família analisados, exceto em C. grandocule, independentemente de seu habitat ou origem. As espécies analisadas do grupo Jordani (C. estor, C. promelas e C. humboldtianum) apresentaram altos níveis de DHA e EPA baixos (<0,5%), como relatado anteriormente para C. estor cultivado. O baixo nicho trófico desses aterinopsídeos e sua capacidade de acumulação de ácidos graxos são fatores que tornam essas espécies notáveis candidatas à aquicultura sustentável.

ABSTRACT Docosahexaenoic acid (DHA) is the most critical and least available omega-3 fatty acid in the Western human diet. Currently, the source of omega-3 long chain polyunsaturated fatty acids (LC-PUFA) is mainly dependent on wild fisheries, making this resource unsustainable in the foreseeable future. In recent years, a high rate of biosynthesis and accumulation of DHA has been discovered in a freshwater species (Chirostoma estor) belonging to the Atherinopsidae family. Interest in evaluating fatty acid composition in other members of the family has emerged, so this study compiles original data of flesh composition of eight atherinopsid species from freshwater and brackish environments, either wild or cultured. High levels of DHA (16 to 31%) were found in all analyzed members of the family, except in C. grandocule, independently of their habitat or origin. The analyzed species of the Jordani group (C. estor, C. promelas and C. humboldtianum) showed high DHA and low EPA levels (<0.5%) as previously reported for cultured C. estor. The low trophic niche of these atherinopsids and their fatty acid accumulation capabilities are factors that make these species noteworthy candidates for sustainable aquaculture.

ABSTRACT This study evaluated growth responses of white shrimp Litopenaeus vannamei by testing different combinations of Jatropha curcas kernel meal (JCK) and tilapia waste silage (FS) as dietary protein sources under laboratory and pond conditions. A reference diet (RD) based on fish meal was elaborated to contain 35% crude protein and 434 kcal/g; then, five isoproteic and isoenergetic experimental diets were formulated from RD with different FS/JCK proportions as follows: 75%FS/0%JCK; 56.25%FS/13.25%JCK; 26.5%FS/30.89%JCK; 18.75%FS/39.75%JCK; and 0%FS/53%JCK. For the laboratory trial, shrimp (2.90 g) were stocked at 10 m2 in an indoor recirculating system during 90 days. There were differences among the growth parameters of diets. Mean weight gain fluctuated from 6.71±0.61 g observed for the shrimp fed the 75%FS/ 0%JCK diet, to 9.70±0.61 g for the group fed the RD. The RD and 18.75%FS/39.75%JCK diet obtained the highest mean final weight (above 12 g), weight gain (above 9 g), and specific growth rate values (above 1.6%/day). Average final survival was 90.97%. The RD and 18.75%FS/39.75%JCK diets were used for the pond trial. Shrimp (0.49 g) were stocked at 10 m2 within 1-m3 cages into the pond for 35 days. Weight gain (3.47 g) and survival (93.33%) of shrimps were similar between the diets. Quadratic equations with the laboratory data indicated that the maximum responses for growth parameters correspond to FS and JKC inclusion levels in the range of 27.83 to 29.00%, and 32.25 to 33.64%, respectively. A combination of 18.75% FS/39.75%JCK meals as protein source is a potential alternative to effectively substitute FM in practical diets for L. vannamei at the studied ages under both laboratory and pond conditions.