Broodstock Diets Research Articles

Effect of protein and lipid levels in diets for female red claw crayfishCherax quadricarinatuson quality of offspring (juvenile), with emphasis on growth performance, biochemical composition and stress resistance to low oxygen, high ammonia and salinity

This study measures the effect of protein and lipid levels in broodstock diet on the quality of juvenile Cherax quadricarinatus. Diets with different contents of crude protein (180, 250, 310, 370 g kg−1) and lipids (30 and 70 g kg−1) were offered to female crayfish. Juveniles were used to assess initial weight (IW), biochemical composition (BC) and survival to stress tests (ST). After 50 days, growth was estimated. No significant effects of broodstock diet on IW and BC of juveniles were detected. Protein content (PC) significantly influenced growth (P < 0.05), with an optimum level of 250 g kg−1, representing a weight gain of 1.17 g (98.08% body weight). PC significantly influenced survival of juveniles exposed to ST (P < 0.05). Results from fitting dose–response models indicated that maximum survival was obtained with PC above 261, 258 and 312 g kg−1 for hypoxia, salinity, ammonia tests. No significant effect of dietary lipid level was observed on growth and survival to ST, except for greater survival to ammonia ST at lipid content of 70 g kg−1. We recommend feed with PC of 260 g kg−1 to simultaneously enhance growth and quality of juveniles.

Reproductive Biology and Effect of Arachidonic Acid Level in Broodstock Diet on Final Maturation of the Hawaiian Limpet Cellana sandwicensis

This study examined the natural spawning season of the Hawaiian limpet or opihi Cellana sandwicensis, by monthly measurement of Gonado Somatic Index (GSI) and histology analysis of the gonad of the animals over the course of a year. The highest GSI values were found in November 2011, January 2012 and from November to December 2012. These GSI values were significantly higher than GSI of opihi collected from other months, suggesting a spawning season for C. sandwicensis from November to January. Significantly lower GSI values were observed from February to September 2012 indicate that opihi were in a resting phase, followed by a final maturation phase which began in October. This study provided an important exogenous key factor for developing an affective induction of opihi gonad maturation in the laboratory. The final maturation of opihi was investigated by supplementation of arachidonic acid (ARA) in the broodstock diet, fed to the animals during the natural final maturation and spawning season. Adult opihi (3.07 ± 0.22 cm in shell length) were fed with two different dietary levels of ARA, 0.24% and 0.39% at the same ARA/EPA (eicosapentaenoic acid) ratio of 0.7 for 95 days. The GSI values of opihi reached to final maturation stage of 24.5% and 23.7% for 0.24% ARA and 0.39% ARA diets respectively, and were significantly higher than GSI of opihi (6.11%) that were fed with the control diet without supplementation of ARA after 75 days. The average eggs diameters were 123 ± 4.23 μm for 0.24% ARA and 121 ± 5.93 μm for 0.39% ARA diets. Histology analysis also confirmed that the eggs were ripe. However, these mature opihi did not undergo to natural spawning and GSI values were winding down after 95 days, suggesting that a natural reabsorption had occurred. The results of this study indicate that supplementation of ARA to EPA ratio of 0.7 during the correct photoperiod were found to have potential for inducing final maturation in limpets.

Essential oils in the initial phase of broodstock diets of Nile tilapia

This study evaluated the effect of feed supplementation (at doses of 0, 50, 100, 150, and 200 mg/kg) with SALUTO®, a microencapsulated blend of essential oils including carvacrol, cinnamaldehyde, 1,8-cineol, and pepper oleoresin, in Nile tilapia (Oreochromis niloticus) broodstock on reproductive and growth parameters during the initial phase of rearing. The growth parameters, somatic indexes and gonadal and hepatic parameters were analyzed. Quantitative parameters of growth, ovary fat and crude protein were not affected by supplementation of the additive. However, an increase in crude protein in the female liver was observed in correlation with increased essential oil levels. The female hepatosomatic index was also correlated with supplementation of essential oils. Feeding Nile tilapia broodstock diets containing an essential oil compound (SALUTO®) affects only the females, promoting an increase in liver protein inclusion and hepatosomatic index without impairing performance.

Maternal reproductive exhaustion in a broadcast spawning marine finfish cultured for conservation

Reproductive exhaustion can be defined as a decline in reproductive potential or output over time. We studied seasonal maternal reproductive exhaustion in a large, freely mating captive population of white seabass (Atractoscion nobilis), a marine finfish cultured in southern California for conservation. Using genetic parentage data, we identified 34 single-maternity spawns produced during the 2008 spawning season and quantified four physical egg characteristics for each spawn, including egg volume (EV), oil volume (OV), percent oil volume (POV), and the number of oil globules (NOG). The mean batch egg measures decreased between the beginning and end of the spawning season by 19%, 45%, 33%, and 12%, respectively. OV and POV declined linearly, whereas the trend in NOG was parabolic and negatively correlated to water temperature and light duration, which reach apices mid-season. EV displayed a similar, though not significant, trend. We also evaluated the egg measures within and among six dames that solo-spawned two or more times. The seasonal trends were similar to those observed at the population-level, but the relative measures varied significantly among dames, indicating factors other than the common broodstock diet and holding conditions may influence egg production in individual A. nobilis females. In terms of species conservation, assessing these egg characteristics, some of which may be associated with larval quality in A. nobilis, in conjunction with estimating genetic diversity for each spawn is important when choosing spawns to rear for stock supplementation, but more research into their relationship with subsequent offspring quality is warranted.

Effects of dietary n-3 to n-6 fatty acid ratios on spawning performance and larval quality in tongue soleCynoglossus semilaevis

This study investigated the effect of n-3 to n-6 fatty acid ratios in broodstock diets on reproduction performance, fatty acid composition of eggs and gonads of tongue sole Cynoglossus semilaevis. Broodstock were fed five isonitrogenous and isoenergetic diets for 60 days. The supplemented lipids were prepared by a combination of fish oil and soybean oil inclusion FO (fish oil); FSO1 (fish oil: soybean oil = 7:1); FSO2 (fish oil: soybean oil = 2.2:1); FSO3 (fish oil: soybean oil = 1:1); FSO4 (fish oil: soybean oil = 1:4.3) as lipid sources with different n-3 to n-6 fatty acid ratios 10.40, 5.21, 2.81, 1.71 and 0.87. Results showed that relative fecundity, fertilization rate and survival rate of larvae at 7 days posthatching were all higher in broodstock fed FSO1 and FSO2 diet and significantly (P < 0.05) decreased in groups fed FSO3 and FSO4 diets. The best result in starvation tolerance test was obtained in FSO2 diet. The present study suggests that n-3 and n-6 PUFA ratio in broodstock diet has a considerable effect on spawning performance, egg and larval quality for C. semilaevis.

The effect of cyclooxygenase (COX) inhibitors on Japanese medaka (Oryzias latipes) reproduction parameters fed with high level of arachidonic acid (20:4 n-6)

Broodstock of mature Japanese medaka (Oryzias latipes Temminck and Schlegel, 1846) (mean weight 0.45 ± 0.03 g; age 6 months) were maintained in glass aquaria (8 males and 8 females in each aquarium). The fish were fed commercial feed (group C) or this feed was supplemented with arachidonic acid ARA (2 % of total fatty acids in feed; group A) and one of the COX inhibitors: resveratrol (group AR) or NS-398 (group ANS) with amount 20 mg kg−1 BW day−1 of one of the COX inhibitors. The effect of 2 weeks of feeding experimental diets on reproductive parameters (fecundity, embryo and larval survival, hatching rate, and larvae body weight) was analyzed. Larvae (obtained from experimental dietary treatments) were reared for 2 weeks. The percent of spawning female and fecundity was similar in dietary treatments. COX inhibitors in broodstock diet caused a decrease in embryo survival rate. Eggs of medaka from group ANS and AR revealed the lowest hatchability rate. In contrast, group A revealed a higher hatchability rate at the same time. Larval body weight after hatching was significantly the highest in this group. At the end of the experiment, larvae body weight ranged from 1.62 ± 0.43 mg in group AN to 2.89 ± 0.74 mg in group A. These results show that the COX inhibitors decreased gamete and larval quality regardless of high levels of ARA in broodstock diet.

Influence of broodstock diet on somatic growth, fecundity, gonad carotenoids and larval survival of sea urchin

The effects of formulated feeds on Paracentrotus lividus broodstock performances and carotenoid compositions were investigated. Performance of offspring derived from each dietary treatment was compared to determine whether maternal provisioning of nutrients affected offspring development and survival under commercial culture conditions. At the end of the experimental period (3 months), urchins were induced to spawn, relative fecundity measured, and offspring derived from each treatment were reared independently and survival up to competence assessed. Carotenoid composition of the gonads was also measured. Data showed that the highest dietary protein content significantly improved somatic growth, whereas higher lipid content increased gonadal index (GI) consistent with the use of gonads as nutrient storage in sea urchins. Nonetheless, gonad lipid concentration was not significantly different between treatments indicating that higher dietary lipid content favoured gonadal size rather than increase lipid content of the gonadal tissue. Interestingly, GI and fecundity were not correlated, although the latter may have been enhanced by dietary xanthophyll. This suggests the importance of including carotenoids in broodstock diets to enhance hatchery outputs. This study also indicated that, although broodstock diet can influence fecundity, it had no significant impact on larval survival, which could instead be influenced by rearing conditions.

A holistic approach to development of diets for Ballan wrasse (Labrus berggylta) – a new species in aquaculture

Wild wrasses are used for delousing of farmed salmon but increasing demands have prompted the salmon industry to develop cultures of Ballan wrasse. One of the bottlenecks has been nutrition and feed intake in the juvenile phase, while broodstock nutrition is considered critical for production of viable offspring. The present study was aimed at developing functioning ongrowing and broodstock diets for Ballan wrasse. In juveniles the best lengthwise growth was identified at 65% dietary protein, 12% lipid and 16% carbohydrate. To investigate if the requirements for the other nutrients were covered by the diets developed for the species, the nutrient composition in juveniles (whole body) and broodstock (female gonad) were analyzed and compared to the composition in wild fish. We found that the levels of the lipid soluble Vitamins A, K and D were lower in cultured than in wild fish, however, the requirements for these nutrients in Ballan wrasse are not known. Other candidate nutrients for more in-depth investigation are the bone minerals, zinc, taurine and fatty acids.

Internal nutrient management associated with gonad quality and successful reproduction in the winged pearl oyster Pteria sterna

The winged pearl oyster Pteria sterna sustains the Mexican pearl industry, but recent problems ensuring the provision of spat for grafting operations have refocused research toward gonad maturation and hatchery production of spat. We used several indicators (morpho-physiological indices, histology, histochemistry, proximal and fatty acid composition) to analyze the management of nutrients involved in gonad quality, larval vigor, and successful reproduction of the species during its natural breeding season. Samples included two ripening peaks (February and April 2009), a pre-reproductive period (November 2008) and a post-reproductive period (June 2009). The indicators were related to changes in water temperature. Spawning occurred in February, April, and June, but the highest gonad quality to sustain larval development and spat production occurred only in April (water temperature was 21.8°C). Also in April, post-vitellogenic oocytes were more abundant, attained larger sizes, and had high protein, lipid, triglyceride, and EPA contents. SAFA, rather than MUFA or PUFA, were actively accumulated in the gonad and digestive gland during the breeding season (February–June), indicating these fuels are reliable criteria of gamete quality. This finding provides information that has relevance in preparing suitable diets for broodstock and larvae, facilitating development of more effective hatchery protocols, and with this, increasing the supply of oysters for grafting operations. For that, we recommend inducing P. sterna to spawn over-ripe gametes in early winter and allow them to redevelop into new gametes of higher quality in early spring when the water temperature reaches 22°C.

Effect of binder type and concentration on prepared feed stability, feed ingestion and digestibility ofLitopenaeus vannameibroodstock diets

The effect of six different binding agents (agar, sodium alginate, cassava starch, gelatin, wheat gluten and kelp meal) in two concentrations (30 g kg−1 and 50 g kg−1) were evaluated with respect to physical quality of Litopenaeus vannamei broodstock pelleted feed, after 15, 30, 60, 90, 120, 150 and 180 min of water immersion. The best treatments in terms of water stability, water absorption and protein leaching were obtained with sodium alginate and wheat gluten at 50 g kg−1. In a second experiment, the feed ingestion and diet digestibility with these two binders and their combination (1 : 1) were compared against a control diet containing 50 g kg−1 wheat flour. There were no significant differences (P > 0.05) in the daily feed ingestion rate 2.39–3.33% of the biomass. The most representative values of apparent digestibility of protein (ADP) and apparent dry matter digestibility (ADMD) were achieved with diets containing wheat gluten and alginate + gluten mixture as binder. Based on these results, combinations with 50 g kg−1 wheat gluten is recommended as binder in pelleted feed for broodstock L. vannamei.

The effects of dietary n−3 series fatty acid on the fatty acid composition, cholesterol and fat-soluble vitamins of pleopodal eggs and stage 1 juveniles in a freshwater crayfish, Astacus leptodactylus (Eschscholtz)

To investigate the effects of dietary n−3 series fatty acid levels on the fatty acid composition, cholesterol and fat-soluble vitamins of pleopodal eggs and stage 1 juveniles in Astacus leptodactylus one control (D1) and three experimental diets (D2, D3 and D4) were prepared. n−3 series fatty acids were not included in the control diet, however, D2, D3 and D4 diets were supplemented with n−3 series fatty acids (n−3 series fatty acid concentrated from anchovy oil and contains 54.3% eicosapentaenoic acid, 37.1% docosahexaenoic acid and 8.6% other n−3 series fatty acid; docosapentaenoic, linolenic, stearidonic acid) at 1%, 2% and 3% level, respectively. Crayfish were fed these isonitrogenous (35% crude protein) and isocaloric (3600kcalkg−1 gross energy) formulated diets for 251days. The results showed that the dietary n−3 series fatty acids improved the chemical quality of pleopodal eggs and stage 1 juveniles (i.e., fatty acid composition, cholesterol and fat-soluble vitamin content). The results also showed that the fatty acid profiles of pleopodal eggs and juveniles were similar to the fatty acid profiles of D1, D2, D3 and D4. In general, increasing concentrations of dietary n−3 series fatty acids lowered the deposition of linoleic acid (18:2n−6) and total n−6 PUFA (polyunsaturated fatty acids), but simultaneously improved the deposition of linolenic acid (18:3n−3), stearidonic acid (18:4n−3), eicosapentaenoic acid (20:5n−3), docosapentaenoic acid (22:5n−3), docosahexaenoic acid (22:6n−3) and total n−3 PUFA in the eggs and juveniles. However, the levels of cholesterol and fat-soluble vitamins in pleopodal eggs and stage 1 juveniles were unaffected by the dietary n−3 series fatty acids (except δ-tocopherol, vitamin K2 and cholesterol levels of stage 1 juveniles). The best chemical quality in eggs and juveniles was obtained from the crayfish fed D4. In conclusion, n−3 series fatty acid concentrations in broodstock diets significantly improved the quality of pleopodal eggs and stage 1 juveniles in A. leptodactylus.

Effects of dietary soybean lecithin on gonadal development and vitellogenin mRNA expression in the female redclaw crayfishCherax quadricarinatus(von Martens) at first maturation

The effect of increasing levels of dietary de-oiled soybean lecithin (SL) on the ovarian development of female redclaw crayfish, Cherax quadricarinatus, was investigated. Five practical formulated diets were supplemented with 0% (Diet 1), 1% (Diet 2), 2% (Diet 3), 4% (Diet 4) and 6% (Diet 5) SL. Crayfish (initial weight: 25.64 ± 1.53 g) were fed each diet in four replicates for 8 weeks. Crayfish that were fed diets containing ≥2% SL had a significantly higher gonadosomatic index than those fed with Diets 1 and 2 (P 0.05). The fatty acid composition of the hepatopancreas is largely due to the dietary composition. Higher dietary SL yielded a higher percentage of ovarian polyunsaturated and highly unsaturated fatty acids (P < 0.05). Furthermore, the higher content of linoleic acid and alpha linolenic acid in diets may be more important for ovarian development in C. quadricarinatus, as these originate from the hepatopancreas. The hepatopancreatic vitellogenin mRNA expression was the highest in crayfish that received Diet 3. Our results suggest that dietary SL has a positive effect on ovarian development in C. quadricarinatus broodstock, and at least 2% SL should be supplemented in broodstock diets to enhance ovarian maturation during aquaculture.

Transitioning Coho Salmon Broodstock to a Docosahexaenoic Acid (DHA)‐Rich Diet during Vitellogenesis: Effects on Egg Composition and Embryo and Fry Quality

AbstractFemale coho salmon Oncorhynchus kisutch were fed one of two broodstock diets during vitellogenesis to evaluate the contribution of dietary lipids to egg lipids and to assess any embryo or fry quality differences that were attributable to treatment. The diets contained lipids with different fatty acid profiles and carbon stable isotope signatures (δ13C). Diets were formulated by top‐dressing a low‐fat salmon broodstock feed with either sardine oil (fish oil feed) or an algal oil–corn oil blend (algal oil feed). The added oils were balanced for total n‐3 fatty acid content but contained markedly different levels of linoleic acid (LA), eicosapentaenoic acid, and docosahexaenoic acid (DHA). Analysis of δ13C revealed that dietary lipids were significantly incorporated into egg lipids during vitellogenesis and that polar and neutral lipid fractions were equally affected. Eggs of fish in the algal oil treatment group had significantly higher levels of DHA and significantly lower protein content than the eggs of fish in the fish oil treatment group. Embryo survival and fry survival and growth were similar between the two treatment groups. Eggs from the algal oil treatment additionally had higher levels of LA, and there was evidence of direct elongation of LA to eicosadienoic acid (20:2[n‐6]) and bioconversion of LA to arachidonic acid by the fish. Results from this experiment demonstrate the feasibility of increasing the DHA content of egg lipids in cultured salmonids without a concomitant decrease in egg or fry quality. The proposed enrichment would allow for the production of a value‐added, high‐DHA product for the cured roe market without reducing the value of eggs that are destined for the hatchery market.

The influence of captive breeding on the fatty acid profiles of Salminus hilarii (Characiformes: Characidae) eggs and larvae

In addition to the strong influence of the broodstock diet on the development and survival of offspring, domestication may also interfere with the larval life success. We obtained eggs from wild and domesticated Salminus hilarii females and domesticated males. Wild females were caught in the Tiete River and tributaries, and the domesticated females were born three years before the beginning of the experiment in the Ponte Nova Fish Farm. Animals from both groups were fed with the same feed to exclude feed variables. The eggs and larvae were sampled at 0, 8, 16, and 28 h after spawning (HAS), with the last sampling (28 HAS) coinciding with hatching time. After hatching, samplings proceeded at 32, 48, 66, and 96 HAS, with the last sampling (96 HAS) corresponding to the end of yolk sac consumption. Finally, the last experimental period was during the larvae exogenous feeding phase, at 102, 118, 166, and 214 HAS. Our data revealed that domestication of S. hilarii females influenced fatty acid (FA) metabolism during embryo and larva development. However, the structure of membrane phospholipid FA remained mostly stable, with changes principally in the neutral fraction. When the external conditions, mainly water and feed quality, remained constant, domestication of S. hilarii females did not significantly affect the structural FA composition but influenced the selectivity of consumption and/or storage of specific FA.

Differences in fatty acid composition of egg capsules from broodstock spotted babylon, Babylonia areolata, fed a local trash fish and formulated diet under hatchery conditions

This study was the first attempt to condition broodstock Babylonia areolata using the formulated diets under hatchery conditions. Samples of spotted babylon egg capsules from broodstock, which had been fed either a formulated diet or a local trash fish, carangid fish (Seleroides leptolepis) for 120 days were analyzed for proximate composition and fatty acid composition. The formulated diet contained significantly higher levels of arachinodic acid (ARA) (20:4n-6), eicosapentaenoic acid (EPA) (20:5n-3) and docosahexaenoic acid (DHA) (22:6n-3) than those of the local trash fish. The formulated diet also had significantly higher ratios of DHA/EPA and (n-3)/(n-6) polyunsaturated fatty acids (PUFA) than those of the local trash fish but not for ARA/EPA ratio. The fatty acid compositions of egg capsules produced from broodstock fed formulated diet contained significantly more ARA, EPA and DHA compared to the broodstock fed the local trash fish. The ARA/EPA and DHA/EPA ratios in egg capsules were significantly higher in the trash fish–fed group compared to those fed the formulated diet. However, (n – 3)/(n – 6) PUFA ratios in egg capsules produced from broodstock fed the formulated diet did not significantly differ compared to those from broodstock fed the local trash fish. The relatively low DHA/EPA, ARA/EPA and (n – 3)/(n – 6) ratios in the egg capsules produced from the formulated diet – fed broodstock of B. areolata suggested that this diet was inferior, when compared to the traditional food of trash fish. Key words: Babylonia areolata, broodstock diet, egg capsules, fatty acid composition.

Examination of broodstock diet effects on egg production and egg quality in flame angelfish (Centropyge loriculus)

This study was conducted to determine the effects of broodstock diet on flame angelfish (Centropyge loriculus) reproduction and generate baseline spawning performance (mean fecundity, egg fertilization, egg viability) and egg biochemistry data for this species. Sixteen flame angelfish broodstock pairs were maintained on one of three formulated diets or a raw diet (consisting of squid, shrimp, fish eggs and algae) to determine the effect of diet composition on the fecundity, egg fertilization rates and egg viability over a 7-month period. Although all the diets supported similar mean spawn frequency and fecundity over the duration of the experiment, the mean fertilization rates and egg viability were significantly greater among pairs receiving the raw diet. Egg fatty acid composition was generally reflective of the maternal diet and similar to the values reported for other tropical species. In particular, dietary factors such as n-3 highly unsaturated fatty acid and ARA level (which were elevated in the raw diet and eggs from fish receiving that treatment) are correlated with egg quality and are therefore worthy of future investigation. Because of the ease of conditioning, adaptability to varied formulated diets and continuous, sustained reproductive output, flame angelfish are an excellent model for examining the factors affecting marine fish egg and larval quality.

Differential Incorporation of Dietary Fatty Acids from Flax and Fish Oils into Lipid Classes of White Bass Ova

AbstractThe extent to which flax oil can replace fish oil in diets fed to female broodstock of white bass Morone chrysops was determined by evaluating growth performance and the fatty acid (FA) profile of ovum lipid classes. Four experimental diets containing increasing levels of flax oil as 0, 33, 67, and 100% replacement of menhaden (Brevoortia spp.) fish oil were fed to female white bass for 30 weeks prior to spawning. Overall, growth and survival were unaffected when flax oil replaced fish oil in the diets. However, ovum FA composition did differ by lipid class and according to dietary intake. The FA profile of the neutral lipid classes largely resembled dietary intake, resulting in monounsaturated FAs (MUFAs) and long‐chain polyunsaturated FAs (LC‐PUFAs; FAs with ≥20 carbons and ≥3 double bonds) as the most predominant FAs found within ova produced by 100% fish‐oil‐fed broodstock, while MUFAs and 18‐carbon PUFAs dominated the ovum neutral lipid in females from the 100% flax oil treatment. Although the phospholipid fraction of ova produced by the 100% flax‐oil‐fed broodstock was also significantly enriched with 18‐carbon PUFAs, accumulation of these FAs did not displace n‐3 LC‐PUFAs as comparable levels of n‐3 LC‐PUFAs were found in both the 100% fish oil and 100% flax oil treatments. Overall, flax oil has potential for use as an alternative to menhaden fish oil in diets for female white bass broodstock without altering phospholipid LC‐PUFA content. However, further investigation is needed to determine how these modifications to ovum FA profile affect embryonic and larval survival.Received January 19, 2010; accepted August 17, 2010

Inclusion of crude palm oil in the broodstock diets of female Nile tilapia, Oreochromis niloticus, resulted in enhanced reproductive performance compared to broodfish fed diets with added fish oil or linseed oil

The intensive farming of tilapia is rapidly expanding and the need to produce sufficient quantities of quality fry is becoming crucial to meet increasing global demands for stocking tilapia farms. The present study was conducted to evaluate the effects of dietary lipid source on the reproductive performance of tilapia broodfish. Four isonitrogenous (35% protein) and isolipidic (10%) casein-based diets were formulated with added fish oil (FO), FO and crude palm oil (FO + CPO; 1:1), CPO or linseed oil (LSO) as the lipid source, respectively. Pre-spawning female Nile tilapia ( Oreochromis niloticus, GIFT strain) was individually color-tagged, and six females and two males were stocked into a one-tonne breeding tank. Each diet was fed to two tanks of broodfish and the reproductive performance of 12 individual female fish was monitored over 25 weeks. Female broodfish fed the two CPO-based diets showed significantly (P < 0.05) larger gonad sizes and lower intraperitoneal fat compared to fish fed the FO or LSO diets. First spawning occurred earliest in broodfish fed the CPO diet at 30.8 ± 9.9 days compared to 44.1, 45.5 or 76.3 days for fish fed the FO + CPO, FO or LSO diet, respectively. The highest number of actively spawning tilapia was observed in fish fed the FO + CPO diet, followed by fish fed the CPO, FO or LSO diet, respectively. At the end of 25 weeks, tilapia fed the two CPO-based diets produced the highest total number of eggs per fish due to the shorter inter spawning interval and higher spawning frequency. Mean diameter, volume and weight of eggs did not vary among dietary treatments. Egg hatchability was significantly higher in broodfish fed the CPO-based diets. The fatty acid composition of the muscle, gonad, egg and newly hatched larvae was influenced by dietary lipid source. However, evidence of preferential fatty acid conservation, conversion and utilization was also observed in these tissues. The fatty acid composition of tilapia eggs did not vary over four consecutive spawns. The gonads, eggs and larvae of tilapia fed the CPO diet contained the highest relative concentration of saturates, monoenes, arachidonic acid and n-6/n-3 ratio. The high total n-3 PUFA concentration observed in the gonads of fish fed the LSO diet, and to a lesser degree the FO diet, seemed to be detrimental to the reproductive performance of tilapia. In conclusion, the inclusion of CPO in tilapia broodstock diets can be a cost-effective method to increase tilapia fry production.

Arachidonic acid is a Major Component in Gonadal Fatty acids of Tropical Coral Reef fish in the Philippines and Japan

The aim of the present study was to investigate the characteristics of gonadal fatty acid composition in 19 species of wild coral reef fish (Serranidae, Lutjanidae, Lethridae, Siganidae and Labridae) from Philippine (11 species of female) and Japanese (8 species of female and 5 species of male) waters with special attention to arachidonic acid (ArA), docosahexaenoic acid (DHA) and eicosapentaenoic acid (EPA) levels and their ratios. ArA levels were always higher than EPA levels in polar lipids of all the species and in neutral lipids in 17 of the 19 species. In ovarian polar lipids of the 19 species, ArA level ranged from 6.0% to 19.4%, while EPA level ranged from 0.9% to 6.2%. Ovarian DHA level was also always higher than EPA in all the species analyzed. Consequently, ArA/EPA ratios of these species were high, unlike cold- and temperate-water species. ArA was the top fatty acid component in testis polar lipids of three Lethrinus species (21.4% to 22.9%). Thus, ArA is not a minor component, that is, the major highly unsaturated fatty acids (HUFAs) of polar lipids in all coral reef fish gonads are DHA and ArA (not EPA). The present information on gonadal fatty acid composition can be used as a guideline for advancing appropriate broodstock diets of tropical coral reef fish, emerging aquaculture commodities in developing countries.

Broodstock diet effect on sea urchin Paracentrotus lividus (Lamarck, 1816) endotrophic larvae development: Potential for their year-round use in environmental toxicology assessment

The effect of captive broodstock diet on fertilization and endotrophic larvae development of the sea urchin Paracentrotus lividus was assessed. Maize grain and five inert pelleted diets were tested, during a three-month experimental period. Maize flour, wheat flour, soybean flour, maize/wheat flour (MWF) and maize/soybean flour mixes were used as vegetal sources for inert feed. Gonad index, percent egg fertilization and larvae malformation occurrence were compared with the results obtained from wild sea urchins (W). Whole egg total amino acid composition was concomitantly analyzed as a tool to explain eventual endotrophic larvae malformations caused by lack of specific nutrients. For all treatment groups (wild and captive), percent egg fertilization values above 96% were always observed, fulfilling the requisites (70–90%) necessary to conduct environmental monitoring bioassays, according to USEPA (2002). Similar values for normal percent larval development were only obtained from P. lividus broodstock subjected to an inert feeding diet based on a maize/wheat flour mix (85.0±1.45%), in comparison to wild P. lividus (82.5±1.75%). Likewise, no statistical differences on resultant whole egg total amino acid composition were observed between P. lividus fed MWF and wild treatments. Moreover, statistical differences between MWF and all the other captive feeding treatments were found for six out of the seventeen amino acids analyzed. This study demonstrates the possibility to obtain high values for P. lividus endotrophic larvae percent normal development based on broodstock held in captivity as long as an appropriate inert diet is provided.