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

RESUMEN En el presente trabajo se evaluó el efecto de diferentes fotoperiodos en la eclosión, crecimiento y supervivencia de larvas de Sphoeroides annulatus. En cada uno de 12 tanques de fibra de vidrio se colocaron 5 g de huevos desgomados y se evaluó la tasa de eclosión, crecimiento en longitud total peso y supervivencia de las larvas bajo cuatro fotoperiodos con tres replicados cada uno: 24 horas luz (hl), 18 hl, 12 hl y 0 hl, durante 45 días después de la eclosión. La tasa de eclosión fue significativamente menor a 0 hl y las larvas no sobrevivieron a los 5 días después de la eclosión. El crecimiento, tanto en longitud como peso, fue significativamente mayor a 12 hl. La supervivencia no presentó diferencias significativas entre los tratamientos. Los resultados sugieren que el fotoperiodo afecta la tasa de eclosión y el crecimiento de las larvas de S. annulatus, bajo las condiciones del presente estudio.

ABSTRACT The objective of the present work was to evaluate the effect of different photoperiods on hatching, growth and survival of Sphoeroides annulatus larvae in order to improve the existing culture protocol. In each of the 12 fiberglass tanks, 5 g of degummed eggs were placed and the hatching rate, growth in total length, weight and survival of larvae were evaluated under four photoperiods with three replicates each: 24 hours light (hl), 18 hl, 12 hl and 0 hl, for 45 days after hatching. Hatch rate was significantly lower at 0 hl and larvae did not survive to 5 days after eclosion. Growth was significantly higher at 12 hl. Survival did not show significant differences between treatments. The results suggest that photoperiod affects the hatching rate andgrowth of S. annulatus larvae under the conditions of this study.

ABSTRACT Continuous illumination has been known to exert positive effects by stimulating growth and delaying unwanted maturation in seasonal-temperate farmed fish species like salmonids. However, in tropical fish like Nile tilapia ( Oreochromis niloticus ), some studies exist showing inconsistent results and even fewer data is available regarding the effects of light intensity. To clarify some of the inconsistent results in literature and evaluate the effect of different light intensity levels on growth and sexual maturation in Nile tilapia ( Oreochromis niloticus ), we reared twenty days post-hatch Nile tilapia larvae under continuous illumination at three different light intensities and compared against a control photoperiod (12L:12D) up to 118 days post-hatch. A total of 600 fry were used using 75 fry per experimental unit in a previously tested experimental aquarium setup. Fish exposed to high and medium intensity continuous illumination treatments were significantly heavier (13-20%) and longer (6-8%) than fish exposed to the control photoperiod. Importantly, however, the degree of growth enhancement did not vary significantly according to the light intensity used. Feed intake was also higher in all continuous illumination treatments than in the control photoperiod, suggesting that growth benefits might be due to an increase in feed intake, which is not affected by the light intensities used. Gonadal development on the other hand, presented differences between sexes with a delay in spermatogenesis, while an advancement towards ovarian maturation occurred compared with the control fish. These results suggest that continuous illumination can influence both growth and gonadal development in Nile tilapia with no apparent differences between the light intensities tested in this study.

The body mass index (BMI) provides one of the indices used to determine the nutritional status of the population worldwide, where despite the existence of clear recommendations for interpretation and defined as gender, age, race, etc. usually their classification, independent of the variables is standardized, increasing the error in the result and classification of nutritional status. The use of body composition through anthropometry, delivers more information than BMI, being fat mass and muscle mass leading useful results. This article presents a review of existing and proposed those equations simpler and less error estimate to be used as a tool to replace or supplement to BMI, promoting a better understanding and interpretation of nutritional status and level of physical activity in children and adolescents.

El índice de masa corporal (IMC) otorga uno de los índices más usados para determinar el estado nutricional de la población a nivel mundial, donde a pesar de existir recomendaciones claras y definidas para su interpretación como el sexo, edad, raza, entre otros, normalmente se estandariza su clasificación, independiente de las variables, aumentando el error en el resultado y en la clasificación del estado nutricional. El uso de la composición corporal a través de la antropometría entrega mayor información que el IMC, siendo la masa grasa y la masa muscular los principales resultados útiles. Este artículo presenta una revisión de las ecuaciones existentes y propone aquellas más simples y con menor error de estimación para ser usadas como una herramienta que reemplace o complemente al IMC, favoreciendo una mejor comprensión e interpretación del estado nutricional y nivel de actividad física en niños y adolescentes.