Dietary Supplementation with Fumaric Acid Improves Growth Performance in Nile Tilapia Juveniles.

Organic acids have recently been identified as promising replacements for antibiotics in aquafeeds that promote fish growth and feed efficiency. This study evaluated the inclusion of fumaric acid (FA; 0, 5, 10, 15, 20, and 30 g/kg) in diets (350 g/kg CP; 3.4 kcal digestible energy/g) of Nile tilapia juveniles. Fish (average weight 1.7 ± 0.1 g) were distributed in three 40 L aquaria per treatment (13 fish/aquaria) in a completely randomized design. Over 35 days, the fish received the experimental diets three times daily to apparent satiety. The maximum weight gain, feed efficiency ratio, and protein efficiency ratio were recorded in fish supplemented with 14-15 g/kg FA. After 28 days, Enterobacteriaceae was registered only in the gut of tilapia without FA augmentation. Gram-negative bacteria in the fish gut decreased (p < 0.05) in fish receiving 17 g/kg of dietary FA, increased after this level. The intestinal villi height and width were affected (p < 0.05) by FA levels and feeding time. Thus, inclusion of 15 g/kg of FA was effective in promoting growth, improving intestinal morphometry, and decreasing negative gut bacteria of Nile tilapia juveniles after 35 days.

Apparent digestibility of conventional and alternative feedstuffs by hybrid tambacu juveniles.

The apparent digestibility coefficients (ADC's) of dry matter (DM), crude protein (CP), and gross energy (GE) of conventional feedstuffs (cottonseed meal-CSM, soybean meal-SBM, wheat bran-WHB, corn-COR) and regional alternative feedstuffs (common bean residue meal-CBR, mesquite meal-MES, pasta by-product meal-PBM) were determined for hybrid juvenile tambacu Colossoma macropomum × Piaractus mesopotamicus. The apparent DM and GE digestibility of feedstuffs decreased (p<0.05) as fiber content of the ingredients increased. No differences (p>0.05) were found among ADC's of PBM and COR. The lowest CP ADC among energy sources was observed in MES; the lowest CP ADC among plant protein sources was observed in CBR. Information about the ADC's of conventional and alternative feedstuffs for tambacu is essential to formulate low-cost diets and can contribute to regional development.

Apparent digestibility of conventional and alternative feedstuffs by hybrid tambacu juveniles

ABSTRACT The apparent digestibility coefficients (ADC's) of dry matter (DM), crude protein (CP), and gross energy (GE) of conventional feedstuffs (cottonseed meal-CSM, soybean meal-SBM, wheat bran-WHB, corn-COR) and regional alternative feedstuffs (common bean residue meal-CBR, mesquite meal-MES, pasta by-product meal-PBM) were determined for hybrid juvenile tambacu Colossoma macropomum × Piaractus mesopotamicus. The apparent DM and GE digestibility of feedstuffs decreased (p<0.05) as fiber content of the ingredients increased. No differences (p>0.05) were found among ADC's of PBM and COR. The lowest CP ADC among energy sources was observed in MES; the lowest CP ADC among plant protein sources was observed in CBR. Information about the ADC's of conventional and alternative feedstuffs for tambacu is essential to formulate low-cost diets and can contribute to regional development.

Growth and intestinal morphology of juvenile pacu Piaractus mesopotamicus (Holmberg 1887) fed dietary prebiotics (mannanoligosaccharides - MOS).

Intensification of aquaculture production systems exposes fish to numerous stressors, which may negatively affect their growth and limit profitability of aquaculture systems. This study determined effects of increasing levels of dietary mannanoligosaccharides on growth and intestine morphology of pacu. Fish (44.04 g) were randomly distributed into 32 tanks (500 L; 10 fishes per tank) and fed during 63 days with a commercial diet supplemented with 0.0; 0.2; 0.4; 0.6; 0.8; 1.0; 1.5 and 2.0% dietary mannanoligosaccharides. Growth parameters did not differ (P>0.05) between fish fed control diet and mannanoligosaccharide supplemented diets. Intestinal villi perimeter was performed in fish fed control diet, 0.4 and 1.5% dietary mannanoligosaccharides and also showed no differences (P>0.05) between treatments. Dietary supplementation of mannanoligosaccharides unclear did not have effects on pacu. Studies on the characterization of intestinal microbiota together with experiment that reproduce commercial fish production systems rearing conditions are necessary to determine the effective use of this dietary supplement for the species.

Growth and hematology of juvenile pacu Piaractus mesopotamicus (Holmberg 1887) fed with increasing levels of vitamin E (DL-α-tocopheryl acetate).

Intensive fish production systems are characterized by 100% artificial feeding, so any dietary imbalances or deficiencies may lead to diseases outbreaks and economic losses. This study was set out to determine the effects of increasing levels of dietary vitamin E on growth and hematology of juvenile pacu. Fishes were fed for 90 days, twice a day until apparent satiation with semi-purified diets containing 0.0; 25; 50; 150; 300 or 600 mg.kg-1 diet DL-α-tocopheryl acetate in a completely randomized design trial (n=4); biometrical and hematological data were collected and analyzed. Fishes fed with vit E diet (150 mg.kg-1) showed higher (p<0.05) weight gain and specific growth. Hematocrit, erythroblast number and total plasma protein were increased (p<0.05) in fishes fed diet with no vit E diet. Vitamin E supplementation in artificial diets for pacu is essential for growth and maintenance of normal erythropoiesis.

[Anisakidae larvae (Nematoda: Ascaridoidea) parasites of the bluewing searobin Prionotus punctatus (Bloch, 1793) (Osteichthyes: Triglidae) from the coastal zone of the State of Rio de Janeiro, Brazil]. / Larvas de Anisakidae (Nematoda: Ascaridoidea) parasitas da cabrinha Prionotus punctatus (Bloch, 1793) (Osteichthyes: Triglidae) do litoral do Estado do Rio de Janeiro, Brasil.

Eighty specimens of Prionotus punctatus (Bloch, 1793) from Angra dos Reis, coastal zone of the State of Rio de Janeiro (23 degrees 01 'S, 44 degrees 19 'W), were necropsied to study their metazoan parasites. Three species of larval nematodes anisakids were found, Anisakis sp., Hysterothylacium sp. and Raphidascaris sp. from the liver and mesenteries. These nematodes are described and a revision of available literature concerning nematodes belonging to these genera was made.

[Metazoan parasites of the bluewing searobin Prionotus punctatus (Bloch, 1793) (Osteichthyes: Triglidae) from the coastal zone of the State of Rio de Janeiro, Brazil]. / Metazoários parasitos da cabrinha Priotus punctatus (Bloch, 1973) (Osteichthyes: Triglidae) do litoral do estado do Rio de Janiero, Brasil.

Eighty specimens of P. punctatus from Angra dos Reis, coastal zone of the State of Rio de Janeiro (23 degrees 01'S, 44 degrees 19'W), were necropsied between May 2002 to August 2003 to study their infracommunities of metazoan parasites. Were collected 23 species of metazoan parasites: 4 digenean, 2 monogeneans, 2 cestodes, 2 acantocephalans, 6 nematodes, 3 copepods, 2 branchiura, 1 isopod and 1 hirudinean. All fishes were parasitized by two or more parasites species. The nematodes was the predominant taxon (58.6% of parasites collected). Hysterothylacium sp. was the most prevalent, abundant and dominant species. The total of parasites collected and the parasites species richness were significantly correlated with host's total length. Ten species of parasites showed significantly correlation between parasites abundance and total length of P. punctatus. The sex of the host showed positive influence on abundance and prevalence of Hysterothylacium sp., Progrillotia dollfusi Carvajal and Rego, 1983 and Dolops sp. Four pairs of adult endoparasites, one pair of endoparasites larval stages and two pairs of ectoparasites presented association and/or covariation between its prevalences and abundances, respectively. Quantitative dominance of endoparasites in the parasite community of P. punctatus could be related with the predatorious behavior of this fish.