http://aerg.canberra.edu.au/library/sex_general/2002_Devlin_Nagahama_sex_determination_in_fish_review.pdf

Sex determination and sex differentiation in fish: an overview of genetic, physiological, and environmental influences

For more than 200 years, the metabolic response that accompanies meal digestion has been characterized, theorized, and experimentally studied. Historically labeled “specific dynamic action” or “SDA”, this physiological phenomenon represents the energy expended on all activities of the body incidental to the ingestion, digestion, absorption, and assimilation of a meal. Specific dynamic action or a component of postprandial metabolism has been quantified for more than 250 invertebrate and vertebrate species. Characteristic among all of these species is a rapid postprandial increase in metabolic rate that upon peaking returns more slowly to prefeeding levels. The average maximum increase in metabolic rate stemming from digestion ranges from a modest 25% for humans to 136% for fishes, and to an impressive 687% for snakes. The type, size, composition, and temperature of the meal, as well as body size, body composition, and several environmental factors (e.g., ambient temperature and gas concentration) can each significantly impact the magnitude and duration of the SDA response. Meals that are large, intact or possess a tough exoskeleton require more digestive effort and thus generate a larger SDA than small, fragmented, or soft-bodied meals. Differences in the individual effort of preabsorptive (e.g., swallowing, gastric breakdown, and intestinal transport) and postabsorptive (e.g., catabolism and synthesis) events underlie much of the variation in SDA. Specific dynamic action is an integral part of an organism’s energy budget, exemplified by accounting for 19–43% of the daily energy expenditure of free-ranging snakes. There are innumerable opportunities for research in SDA including coverage of unexplored taxa, investigating the underlying sources, determinants, and the central control of postprandial metabolism, and examining the integration of SDA across other physiological systems.

/pdf/specific-dynamic-action-a-review-of-the-postprandial-18gdectymp.pdf

Specific dynamic action: a review of the postprandial metabolic response

The need for nutritional sources safer than traditional animal products has renewed interest generally in plants and particularly in microalgae. Microalgae have diverse uses in aquaculture, their applications are mainly to provide nutrition and to enhance the colour of the flesh of salmonids. The larvae of molluscs, echinoderms and crustaceans as well as some fish larvae feed on microalgae. Several studies have confirmed that a live multi-specific, low bacterial and microalgal biomass remains essential for shellfish hatcheries. Major advances are expected from new production system, designs and operations from batch run open tanks to more sophisticated continuously-run and closed loop reactors. Currently, studies are underway to examine the cost-effectiveness of the on- and off-site microalgal production systems which can only be achieved by substantial scaling-up and improved quality control. In order to attain sustainability in the usage of microalgae, a systems-based approach is required which integrates different fields such as biotechnology, bioprocess and management procedures.

Microalgae: a sustainable feed source for aquaculture

Penaeoid and Sergestoid Shrimps and Prawns of the World: Keys and Diagnoses for the Families and Genera

Nutrition of Litopenaeus vannamei reared in tanks or in ponds

The feasibility of substituting soybean meal for fishmeal diets for juvenile white shrimp Litopenaeus schmitti (035±001 g) was evaluated, and an adequate substitution level was determined Five diets were evaluated using 46%, 59%, 75%, 88% and 100% substitution levels Pellet water stability was significantly affected by dietary soybean content (P<005) Increased soybean content produced lower pellet stability, ranging from a dry matter loss of 14–22% after a 2-h immersion, and 20–33% after an 8-h immersion After 52 days, significant differences (P<005) were found in shrimp weight, feed conversion ratio and protein efficiency ratio The values were 064–106 g, 28–79 and 045–121, respectively, for the three measurements Overall, better results were obtained with diets where soybean meal was substituted for fishmeal up to 75% The 100% soybean meal diet resulted in poor growth performance of shrimp Survival rates were acceptable for all treatments (90% or higher) and no significant differences were found in survival between treatments Regression analysis using the broken-line methodology indicated that 765±2% is an optimum soybean substitution level in diets that contained fishmeal and soybean as the major protein sources for grow-out of juvenile white shrimp

Substitution of fishmeal with soybean meal in practical diets for juvenile white shrimp Litopenaeus schmitti (Pérez‐Farfante & Kensley 1997)

An experiment was conducted to study the effect of protein level on the growth rate, survival, pre- and postprandial oxygen consumption, and ammonia (N-NH3) excretion in white shrimp. Penaeus setiferus (L.), juveniles. Diets containing 10%, 20%, 30%, 40% and 50% protein were provided at a proportion of 15% of the dry weight of shrimp weighing 0.19 ± 0.01g. The instantaneous growth rate was recorded for 45 days. The optimum protein level, in terms of the best growth rate, was that of the 30% protein diet (1.1 5g45days−1). All shrimp fed with the diets had significantly higher respiration rates after feeding because of the apparent heat increment (AHI). A greater postprandial nitrogen excretion (PPNE) excretion was also observed after feeding. Shrimp maintained on the 30% protein diet had the lowest AHI and PPNE coefficients (percentage of ingested energyl. and took the least time to reach the oxygen consumption and nitrogen excretion peak. The 0:N ratios varied according to protein level, with higher values (32 and 44, fasting and Feeding, respectively) with a 30% protein diet, and lower values (10 and 13. fasting and feeding, respectively) with 10% and 50% protein diets. These results indicate that P. setiferus juveniles use protein when fed with high (50%) and low (10%) protein diets, and lipid-protein substrates with a 30% protein diet. Under these conditions, P. setiferus grow better with a 30% protein diet where shrimp use food more efficiently.

Oxygen consumption and ammonia‐N excretion related to protein requirements for growth of white shrimp, Penaeus setiferus (L.), juveniles

To evaluate the effect of Spirulina platensis inclusion in microdiets for white shrimp Litopenaeus schmitti larvae, a completely randomized experimental design was developed with 4 treatments and three replicates. Diets with 3 inclusion levels (0, 2.5 and 5%) were prepared. A control was fed Artemia nauplii. Larvae were fed for 120 hours from mysis I to postlavae 1 every 4 h, and water quality parameters were measured daily. At the end of the experiment survival was determined, and the development index of the larvae was calculated. The chemical score of the diet was also determined, using the L. schmitti postlarvae amino-acid pattern as reference. Triptophan and hystidine were the first and second limiting amino acids in the diets. Survival was around 80% for all treatments. When compared to the control, final postlarval size was significantly smaller. However, the development index (DI) showed that larvae fed diets containing 5% Spirulina platensis meal was superior to the rest of the diets and similar to the Artemia nauplii (p<0.05).

EFFECT OF Spirulina platensis MEAL AS FEED ADDITIVE ON GROWTH, SURVIVAL AND DEVELOPMENT IN Litopenaeus schmitti SHRIMP LARVAE

Reproductive characteristics of the black grouper Mycteroperca bonaci and the yellow-fin grouper M. venenosa were studied off Cuba. Both species are protogynous, hermaphroditic, and monandric. All individuals of both species change sex usually around 65 cm of total lenght CL T) and after spawning as females at least once. The sex ratios were 30.3 females per male in black groupers and 9.3: 1 in yellow-fin groupers. Ripe females of both species had a size range of 55-60 cm LT. The smallest size in ripe males of M. bonaci was 98 cm LT (71 cm in M. venenosa). The condition factor during ontogeny increases with gonadal development. Both species spawm during winter and spring. Vitelogenesis is asynchronic and spawning is portional in both species. Gonadosomatic index in ripe fishes varied from 0.85 lo 4.96 in females and from 1.44 lo 6.80 in males.

Tsai García

Papers

Substitution of fishmeal with soybean meal in practical diets for juvenile white shrimp Litopenaeus schmitti (Pérez‐Farfante & Kensley 1997)

Oxygen consumption and ammonia‐N excretion related to protein requirements for growth of white shrimp, Penaeus setiferus (L.), juveniles

EFFECT OF Spirulina platensis MEAL AS FEED ADDITIVE ON GROWTH, SURVIVAL AND DEVELOPMENT IN Litopenaeus schmitti SHRIMP LARVAE

Reproducción de Mycteroperca bonaci y Mycteroperca venenosa (Pisces: Serranidae) en la plataforma cubana

Requerimientos de proteína en postlarvas del camarón blanco Penaeus schmitti