Ecology Departmemt

the animals showed a significant difference among the five treatments with phenoloxidase activity Ž. for the Phaffia-treated animals being significantly lower P s 0.003 than any of the other diets except the b-glucan diet. These results indicate that even though no clear immunostimulatory effect could be found for the different treatments, it appears that all three yeasts, and especially the Phaffia diet, had a positive effect on the animals, leading to better survival. The animals on the glucan diet showed poor performance overall, indicating that not only did this treatment not aid in increasing resistance of the animals to infection, but on the contrary, these animals showed reduced performance when compared to the animals fed the control diet.

Six experimental diets were fed to satiety to juvenile Litopenaeus stylirostris (77-mg initial weight) in a 28-day feeding trial with 5 replicates per treatment and 15 shrimp per replicate. Diet 1 contained a fishmeal manufactured from fresh herring and diet 2 from stale herring of the same catch. Diets 3, 4, 5 and 6 contained the fresh herring meal but were supplemented with cadaverine (C) + histamine (H) + putrescine (P) + tyramine (T), CPT, HPT and CH, respectively, to obtain total biogenic amine concentrations similar to diet 2 but in different combinations. Survival, feed consumption and final biomass were significantly lower for the shrimp fed with the stale fishmeal. Individual weight and weight gain were significantly lower only with respect to diet 6 (supplemented with cadaverine and histamine). Feed conversion ratio was not affected by this fishmeal. The addition of amines to the fresh fishmeal had no effect on these parameters, except for diet 6, which displayed higher feed consumption, wet weight and final biomass. Polyamine concentrations of the hepatopancreas and remaining whole body were also measured at the end of

Raw material freshness is an important criterion of fish-meal quality for salmonids and also for swine and broiler starter feeds, but needs to be assessed for shrimp. Three batches of anchovy meal were produced in a commercial low-temperature processing plant in Chile, from a unique Ž . Ž . source of raw fish, either fresh FR, 12 h post capture , moderately fresh MF, 25 h post capture Ž . or stale ST, 36 h post capture . Freshness was assessed through the total volatile nitrogen content Ž . in fish before process TVN 14, 30 and 50 mg Nr100 g, respectively , and biogenic amines in Ž fish meal histamine 28, 1850 and 4701 mgrkg, respectively, and also with increasing content of . cadaverine, putrescine and tyramine . Samples of the three fish meals were incorporated at levels of 30% or 40% into isoenergetic diets fed ad libitum to shrimp during various feeding trials. Ž Feeding trials were conducted in Monterrey, Mexico, on Penaeus Õannamei early juveniles 0.9 . and 1.5 g initial weight held in a synthetic seawater recirculating system, and in Tahiti on P. Ž . Ž . Ž . Õannamei 7.6 g , P. monodon 2.5 g and P. stylirostris 8.4 g in a natural seawater Ž . flow-through system. Small P. Õannamei 0.9 g expressed significantly higher feed consumption Ž . Ž . P s 0.028 and percent weight gain P s 0.048 when fed the fresh raw material fish meal:

Dry matter, energy, crude protein and amino acid apparent digestibility coefficients (ADCs) were determined in white shrimp juveniles for six wheat products: hard red winter whole grain meal (HWG), Rayon whole grain meal (RWG), Durum whole grain meal (DWG), hard red winter clear flour (HCF), mixed wheat 2nd clear flour (MCF) and semolina (S). The test diets included 30% of the test ingredients and 70% of a ground commercial diet supplemented with 1% chromic oxide and 1% sodium alginate. Amino acid contents in the ingredients, diets and feces were analyzed, and digestibility was determined by difference in order to minimize the impact of endogenous amino acid losses; crude protein and amino acids ADCs were adjusted for dietary preprandial losses in seawater. In general, nutrients digestibility was far higher in the wheat products than in the fish meal-based reference diet. Dry matter and crude protein ADCs were not statistically different among wheat products (from 84 to 96% and from 88 to 107% respectively). Energy ADCs were significantly higher for clear flours (96% for HCF and MCF) than for whole grain meals and S (from 83 to 86%). Total amino acids (TAA) and essential amino acids (EAA) ADCs, once adjusted for preprandial leaching from the experimental diets, ranged from 81 to 89% and from 58 to 81% respectively, and were statistically comparable among wheat products. Low Thr ADCs appear as a common feature of the amino acids digestibility profiles for whole grain meals, clear flours, or semolina.

Dry matter, energy, protein and amino acid apparent digestibility coefficients (ADC) were determined in Pacific white shrimp juveniles (6 g average initial weight) for four soybean products: full fat soybean meal (FFSBM, 38% CP in dry matter), solvent extracted soybean meal (SBM, 52% CP), soybean protein concentrate (SPC, 71% CP) and soybean protein isolate (SPI, 89% CP), obtained from soybeans processed by different manufacturers in USA and México. The test diets included 30% of the test ingredients and 70% of a ground commercial diet supplemented with 1% chromic oxide and 1% sodium alginate. Amino acid contents in the ingredients, diets and feces were analyzed by HPLC at Evonik-Degussa laboratory. Amino acid profiles of the four soybean product samples were quite similar except for a lower content of methionine and cystine in SPI. In general, nutrient digestibility values were far higher in the soy products than in the fish meal-based reference diet. Dry matter and energy ADCs were significantly higher for SPI (92 and 98%, respectively) than for FFSBM, SBM and SPC (83 and 89%, respective averages). Crude protein ADC was not significantly different among FFSBM, SBM and SPI, but SPC had significantly a lower value (93 vs 96%). Total amino acid (92 vs 97%) and essential amino acid (91 vs 96%) digestibility profiles were almost identical for FFSBM, SBM and SPI, while the SPC profile was parallel but 3.5 to 7 percentage units lower. Cys and Thr were the least digestible amino acids in all samples, while Gly and Arg were generally the most digested. Compared to the ADC of crude protein, the ADCs for Thr and Cys were 3-4% lower, while arginine ADC was 2-3% higher. The ADCs for Lys and Met were similar to that of crude protein, although Lys and Met digestibility may be overestimated due to their high solubility in seawater.

Crur-S&ez. L.E.. Kicque. D. and AQUACOP. 199i. Eifect of squid meal on growth ofPenaPus mo~zodnn juveniles reared in pond pens and tanks. Aqzmcubure, 106: 293-299. Triplicate groups of P. monodon (initial weight 2.2 g) were reared for 40 days (June-lc!y 1985

Recent studies have shown that feeding diets supplemented with fish meal containing high levels of biogenic amines to shrimp reduced growth and feed consumption. An improvement in growth, however, has been found in shrimp fed a diet supplemented with histamine and cadaverine. The objective of the current experiment was to provide more information about the effect of dietary histamine on the growth of blue shrimp Litopenaeus stylirostris and the impact on biogenic amine concentration in shrimp tissues. Six experimental diets were manufactured and supplemented with histamine at 0, 600, 1200, 2400, 3600 and 4800 mg kg y1 and tested in a feeding trial for 28 days. Histamine supplementation did not have any effect on feed consumption, Ž. feed conversion ratio or survival. Weight gain fitted a quadratic dose response curve P-0.05 , y1 Ž with maximum values at 1200 and 2400 mg kg of dietary histamine weight gain being 8.8%. higher than for the control , and lower growth at higher doses. Spermidine concentration in whole shrimp tissue increased linearly with dietary histamine supplementation. It was concluded that dietary histamine supplementation at the levels tested does not have any negative effect on shrimp performance. Moreover, an improvement in weight gain was observed when histamine was supplemented at moderate levels.

Baker's yeast Saccharomyces cerevisiae is a potential supplement in shrimp feeds, but there are few data on yeast survival after feed manufacturing processes. Dry, active yeast cells, agglomerated in spheres of different sizes (100-200 and 800-1600 mm) were incorporated into feeds processed by a commercial pellet mill or in the laboratory using a meat grinder, in order to check their resistance to the process, storage, immersion in seawater, and their effect on the pellet stability in seawater. Total counts (cells seen alive by microscopy evaluation) and viable yeast counts (colony forming units on malt agar plates) were determined in feed samples at different stages of the process. Pelleting had no significant effect on total yeast counts but decreased the viable yeast numbers about 10-fold. The laboratory process was more destructive with a 10 5-fold decrease for both total and viable yeast counts. Immersing the feed pellets in seawater further reduced the yeast number but only by less than 10-fold. Fine yeast spheres (< 200 mm) had a slightly better overall resistance and survival than large yeast spheres (> 800 mm). Pellet stability in seawater was not affected by the inclusion of the yeast agglomerates.

Juvenile shrimp Litopenaeus vannamei (3.5 g initial weight) and green seaweed Ulva clathrata were cocultured in outdoors tanks (2000 L) for 45 days; co-cultured Ulva was suspended on a mesh stretched on the water surface. Four dietary treatments were evaluated: Ulva alone, Ulva + 55% feed ration, Ulva + 90% feed ration, and 100% feed ration (control group without co-cultured Ulva). The control group was fed a commercial pellet (30% protein, 8% fat) at a daily ration of 3.5% shrimp biomass. Water turbidity in co-culture tanks was lower than that in control group. Survival was similar among the experimental groups (>80%). The Ulva intake by shrimp improved the artificial feed conversion ratio and the growth rate: with 10 or 45% less commercial feed, growth rate improved by 60%. Additionally, U. clathrata intake diminished lipids content in shrimp carcass and also modified the fatty acids profile. Shrimp body carotenoids content was significantly higher in the co-culture groups, suggesting that Ulva carotenoids were efficiently assimilated and metabolized, and also may be involved in growth enhancement.

A feeding experiment was conducted to examine the potential of a commercial steam-processed-feather meal (SPFM) and feathers enzymatically hydrolysed for 60 or 120 min (EHF60 and EHF120) as substitutes for ®shmeal (FM) in diets for white-shrimp juveniles. Enzymatically hydrolised feathers or SPFM were blended through an extruder with soyabean meal (SBM) in a 1:1 ratio (EHF-SBM, SPFM-SBM). Isoproteic and isolipidic diets were formulated to contain 9% EHF60-SBM, 9% EHF120-SBM and 18% EHF60-SBM. These diets were compared with a diet containing 13.7% SPFM-SBM and a control diet designed to contain 18.4% FM and no feather. Quadruplicate groups of 15 shrimp (0.33 g initialbody weight) were fed twice a day on each diet for 4 weeks. The weight gain of shrimp fed on the three EHF-SBM diets did not dier from that of shrimp fed on the FM-control diet; however, shrimp fed on the SPFM-SBM diet gained less weight. The EHF60 and EHF120 coextruded with SBM in a 2:1 ratio were evaluated in a commercial rearing pond. Both ingredients included at 20% in the test diets were compared with a control diet containing 17.8% FM. Triplicate groups of juvenile shrimp (3.4 g initial-mean weight), randomly allocated in 1 m 3 plastic cages, were fed with the test diets during 30 days. Growth (weight gain, speci®c-growth rate (SGR)) and nutritional value of the diets, food conversion ratio (FCR), protein-eciency ratio (PER), digestibility were similar. In summary, these results indicate that white shrimp can be fed with a practical diet containing 20% EHF-SBM (2:1) without impairing growth or food conversion. The use of 20% EHF-SBM (2:1) allowed the ®sh-meal portion to be reduced by nearly by 55%.

Stable isotope analyses were applied to explore the relative dietary nitrogen contributions from fish meal and pea meal (Pisum sativum) to muscle tissue of Pacific white shrimp postlarvae (141 ± 31 mg) fed low protein diets having different proportions of both ingredients as the sole dietary protein sources. A negative control diet was formulated to contain 100% pea meal and six more isoproteic diets to have decreasing levels of pea meal-derived nitrogen: 95, 85, 70, 55, 40 and 0 % of the initial level. Growth rates were negatively correlated to dietary pea protein inclusion due to progressive essential amino acid deficiencies (sulfur amino acids, threonine, lysine, histidine). The nitrogen turnover rate significantly increased in muscle tissue of shrimps fed diets having high levels of pea meal; however, contrary to observations from a previous study using soy protein , the relative contributions of dietary nitrogen from pea meal to shrimp muscle tissue were equal or higher than expected contributions established by the dietary formulations. Results highlight the effectiveness of stable isotope analysis in assessing the nutritional contributions of alternative ingredients for aquaculture feeds and the potential suitability of pea as a source of protein (provided the diets are nutritionally balanced).

Recent studies on salmon and shrimp have shown that reduced feed intake and growth caused by the consumption of low-quality ¢sh meals, manufactured from spoiled ¢sh, were not due to the presence of biogenic amines. Moreover, an improvement in weight gain was seen in blue shrimp fed a diet supplemented with cadaverine plus histamine. It was not clear, however, if this e¡ect was due to the consumption of histamine or cadaverine. The objective of the current experiment was to investigate the e¡ect of dietary cadaverine supplementation on growth parameters and various amine concentrations in tissues of the blue shrimp Litopenaeus stylirostris. Six experimental diets were supplemented with cadaverine at 0, 500, 1100, 2300, 3500 and 4600 mg kg À1 and tested in a feeding trial lasting 28 days. Feed consumption, feed conversion ratio, survival and weight gain were not a¡ected by the concentration of dietary cadaverine. The dietary supplementation of cadaverine, however, resulted in a linear increase in cadaverine concentration in shrimp tissues, especially in the hepatopancreas. It was concluded that dietary cadaverine does not have any e¡ect on growth and feed intake of shrimp. Growth promotion, as reported previously in shrimp fed a diet supplemented with histamine plus cadaverine, was probably due to histamine or a combined e¡ect of histamine plus cadaverine but not due to dietary cadaverine alone. It seems that shrimp have a limited ability to metabolize cadaverine, which then accumulates intact in shrimp tissues.

Currently aquaculture is supplying almost half of the world&#x27;s seafood, making it a primary source of high quality nutrients for human consumption and an invaluable export item for many countries. Market prices have increased for many human food sectors; yet, the farm gate value for seafood products have declined or at best had marginal increases in price. Unfortunately, at the same time feed, fuel and processing costs are rapidly increasing pushing many of the world&#x27;s producers to cut their production costs or go out of business. For those who would like to remain in the industry we must be willing to adapt to changing markets and adjust production processes to maximize investment returns. If we are to remain competitive, we must know our cost structures and re-evaluate production practices. It is time for the industry to review there production practices, confirm production values as well as costs so they can bet back to the basics of cost effective management and optimiz...

Background Newcastle Disease Virus (NDV) causes a serious infectious disease in birds that results in severe losses in the worldwide poultry industry. Despite vaccination, NDV outbreaks have increased the necessity of alternative prevention and control measures. Several recent studies focused on antiviral compounds obtained from natural resources. Many extracts from marine organisms have been isolated and tested for pharmacological purposes, and their antiviral activity has been demonstrated in vitro and in vivo. Fucoidan is a sulfated polysaccharide present in the cell wall matrix of brown algae that has been demonstrated to inhibit certain enveloped viruses with low toxicity. This study evaluated the potential antiviral activity and the mechanism of action of fucoidan from Cladosiphon okamuranus against NDV in the Vero cell line. Methods The cytotoxicity of fucoidan was determined by the MTT assay. To study its antiviral activity, fusion and plaque-forming unit (PFU) inhibition as...

The current study quantified the relative contribution of dietary carbon and nitrogen supplied by live biomass of the green macroalgae Ulva clathrata and a commercial inert feed to the growth of juvenile shrimp Litopenaeus vannamei. The stable isotope ratios of carbon and nitrogen (d 13 C and d 15 N) were analyzed in both food sources, whole bodies, and muscle tissue of shrimp reared on co-feeding regimes where 75%, 50%, and 25% of daily consumed macroalgal biomass was substituted by inert feed (regimes 75F/25U, 50F/50U, and 25F/75U, respectively). Higher growth rates were observed in shrimp fed regime 75F/ 25U (k ¼ 0.062), followed by shrimp fed only inert feed (100F, k ¼ 0.060). Animals reared only on U. clathrata (100U) showed minimal growth (k ¼ 0.008) and very high metabolic turnover rates of carbon and nitrogen. Isotopic values measured in inert feed (d 13 C ¼-23.0&, d 15 N ¼ 9.7&) and macroalgae (d 13 C ¼-13.1&, d 15 N ¼-3.5&) were highly contrasting and both had a rapid influence on the isotopic values of shrimp. Animals reached full isotopic equilibrium through growth and fast metabolic turnover in only 2 wk, except shrimp fed macroalgae only. At the end of the experiment, d 13 C and d 15 N values in shrimp reared on all cofeeding regimes were strongly biased toward the isotopic values of U. clathrata. Total dry matter contributions to growth were estimated using an isotope mixing model, and considered the elemental concentration of both nutritional sources. Results indicated that shrimp in the co-feeding regimes incorporated significantly higher amounts of dietary carbon and nitrogen from the macroalgal biomass. Shrimp in treatment 75F/25U incorporated 52% of carbon from the inert feed and 48% from the macroalgae. Animals under feeding regimes 50F/50U and 25F/75U incorporated higher amounts of dietary carbon from U. clathrata (65-89%) when compared with carbon proportions supplied by both co-feeding regimes (33-70%), and also incorporated the majority of nitrogen from the macroalgae. However, a high incorporation of nitrogen was not reflected in larger growth in the latter treatments because metabolic turnover rates were very high. Estimated turnover rates ranged from 0.049-0.191/day for carbon and from 0.013-0.100/day for nitrogen, and values followed an increasing trend as a function of macroalgae consumption. Nitrogen halftimes in tissue consistently decreased throughout the different treatments from 9.5 days (100F) to 6.4 days (100U). Proportions of incorporated nutrients in muscle tissue followed similar patterns as those observed in whole bodies.

Carbon and nitrogen stable isotope values were determined in Pacific white shrimp (Litopenaeus vannamei) with the objective of discriminating animals produced through aquaculture practices from those extracted from the wild. Farmed animals were collected at semi-intensive shrimp farms in Mexico and Ecuador. Fisheries-derived shrimps were caught in different fishing areas representing two estuarine systems and four open sea locations in Mexico and Ecuador. Carbon and nitrogen stable isotope values (δ13CVPDB and δ15NAIR) allowed clear differentiation of wild from farmed animals. δ13CVPDB and δ15NAIR values in shrimps collected in the open sea were isotopically enriched (−16.99‰ and 11.57‰), indicating that these organisms belong to higher trophic levels than farmed animals. δ13CVPDB and δ15NAIR values of farmed animals (−19.72‰ and 7.85‰, respectively) partially overlapped with values measured in animals collected in estuaries (−18.46‰ and 5.38‰, respectively). Canonical discriminant ...

Apparent digestibility coefficients (ADC) of dry matter, crude protein (CP), and amino acids (AA) were evaluated in diets with six rendered by-products used to feed juvenile Pacific white shrimp: two poultry meals (poultry meal 1, 69% CP; poultry meal 2, 72% CP), two feather meals (89% CP), one blood meal (96% CP), and one pork meal (57% CP). Experimental diets were formulated with 30% of the test ingredient and 70% of a commercial diet supplemented with 1% of chromium oxide as inert marker. AA contents in ingredients, diets, leached diets, and feces were determined by high performance liquid chromatography. Preprandial AA losses attributed to leaching were higher in the blood meal diet (15%) and pork meal diet (10%). Poultry meal diets 1 and 2 showed mean AA losses of 3% and 5%, respectively, while the reference diet had a mean AA leaching of 6%. The AA that had the highest leaching rates were lysine (21%), methionine (15%), and histidine (12%). The ADC of dry matter was higher for...

Las micotoxinas son metabolitos secundarios producidos por hongos, especialmente de los géneros Aspergillus, Penicillium, Fusarium y Alternaria, y se pueden encontrar en forrajes y alimentos (Kolossova et al. 2009). Se ha observado Effectiveness of aluminosilicate-based products for detoxification of aflatoxin-contaminated diets for juvenile Pacific white shrimp, Litopenaeus vannamei Efectividad de productos a base de aluminosilicatos en la detoxificación de dietas contaminadas con aflatoxinas para juveniles de camarón blanco del Pacífico, Litopenaeus vannamei

Digestibilidad aparente de carbohidratos y lípidos en alimentos para camarón blanco, Litopenaeus vannamei (Decapoda: Penaeidae), cultivados en diferentes salinidades. Whiteleg shrimp, Litopenaeus vannamei is one of the most commercially farmed species worldwide because of its fast growth, good survival rate at high farming densities, and osmoregulatory capacity, which makes it an excellent candidate for cultures at different salinities. The knowledge of shrimp nutritional requirements is critical in the formulation of diets to allow optimal growth at different environmental conditions and development stages. The effect of salinity on apparent digestibility of shrimp feed is not well known, and this information is required in shrimp diet formulation. For this purpose, the apparent digestibility coefficients of carbohydrates (ACD) and lipids (ALD) were determined for juvenile whiteleg shrimps under controlled culture conditions. We evaluated the apparent digestibility of six commercial (D1:37CP, D2:38CP, D3:39CP, D4:34CP, D5:35CP, and D6:37CP) and two experimental (E1:33CP and E2:33CP) diets for juvenile whiteleg shrimp cultivated at three salinities (5, 35 and 50psu) in 60L aquariums. ACD and ALD were determined in vivo using chromic oxide as an inert marker. Our results showed that ALD in most cases was over 80%, independent of salinity, except the E1:33CPdiet which had 74.0% at 50psu. Diet D3:39CP showed the highest ALD coefficient (90.1 and 90.6% at 5 and 35psu, respectively). For ACD, differences were detected between commercial and experimental diets at every salinity level, although salinity effect on ACD was not significant. Diet D4:34CP had the highest coefficient (92.4%) at 5psu, and E2:33CP at 35 and 50psu (97.3 and 94.7%). This study demonstrated that there is no significant effect of saline variations on carbohydrate and lipid digestibility by juvenile whiteleg shrimp, under the experimental conditions.