Evaluation of use effective microorganisms (EM) with different feeding strategies on growth performance, body chemical composition and economic efficiency of monosex Nile tilapia Oreochromis niloticus juveniles

A factorial trial was conducted to detect the effect of different feeding strategies of supplementation of effective microorganisms (EM) liquid on the growth performance, feed utilization, body chemical composition and economic efficiency of monosex Nile tilapia (Oreochromis niloticus) juveniles. Three experimental treatments were formulated a basal diet without any addition of EM (control; A), a diet supplemented with 2% EM (B), and a diet supplemented with 4% EM (C). All treatments were offered to fish through two different strategies of feeding the meal: 2/3 in the morning and 1/3 in the afternoon or 1/3 in the morning and 2/3 in the afternoon. Each treatment was replicated three times. Juveniles Nile tilapia with an average initial body weight of 3.85 ± 0.22 g (± SE) were randomly stocked at a rate of 90 juveniles per 1.5 m3 tank. Fish growth performance and feed utilization significantly (P ≤ 0.05) increased with increasing EM supplementation and were positively affected by different feeding strategies. Moreover, the economic evaluation showed that there were more benefits by when using the 4% EM diet and feeding 2/3 of daily meal in the morning

Feeding strategies and energy to protein ratio on tambaqui performance and physiology

The objective of this work was to evaluate the effect of feed deprivation and refeeding with diets containing different energy to protein ratios (E/P) on the performance and physiology of juvenile tambaqui (Colossoma macropomum). A 4x2 factorial arrangement with three replicates was used, with four E/P ratios (11.5, 10.5, 9.5, and 8.5 kcal g-1 digestible energy per protein) and two feeding regimens (with and without deprivation), during 60 days. Fish from the food-deprived group were fasted for 14 days and refed from the fifteenth to the sixtieth day, whereas the remaining fish were fed for 60 days. At the end of the experimental period, weight of fish subjected to food deprivation was lower than that of those continuously fed; however, this condition did not influence the physiological parameters analyzed. Tambaqui fed 11.5 kcal g-1 achieved lower final weight than those fed with the other diets, in both regimens. Among the physiological parameters, only plasma protein presented significant increase in fish fed 8.5 kcal g-1, in both feeding regimens, probably due to the higher dietary protein concentration. These results indicate that fish show a partial compensatory growth, and that 10.5 kcal g-1 can be recommended for the diet of juvenile tambaqui

Desempenho e hematologia de tilápias-do-nilo alimentadas com Saccharomyces cerevisiae e vacinadas contra Streptococcus agalactiae

O objetivo deste trabalho foi avaliar a inter-relação entre a suplementação alimentar com parede celular de Saccharomyces cerevisae e a vacinação contra Streptococcus agalactiae e seu efeito sobre o desempenho produtivo e as variáveis hematológicas de tilápia-do-nilo (Oreochromis niloticus). Oitenta e quatro tilápias-do-nilo foram distribuídas em 12 caixas de fibra (n=7), em arranjo fatorial 2x2x3, correspondente a dois níveis de suplementação com parede celular de levedura, dois tipos de inoculação e três tempos de avaliação. Os peixes foram alimentados durante 77 dias. A vacinação dos peixes foi realizada 60 dias após o início da alimentação. Quinze dias após a vacinação, todos os peixes foram submetidos ao desafio com cepa viva de S. agalactiae, e 6, 24 e 48 horas após o desafio, o sangue foi colhido da veia caudal para avaliações. Peixes alimentados com ração suplementada apresentam maior ganho de peso e taxa de crescimento específico, e a interação entre os efeitos da dieta e da vacinação resulta em maiores taxas de hematócrito, hemoglobina e leucócitos

Histologia hepática e produção em tanques-rede de tilápia-do-nilo masculinizada hormonalmente ou não masculinizada

O objetivo deste trabalho foi avaliar o desempenho e a sanidade da estrutura hepática de tilápia-do-nilo, masculinizada hormonalmente ou não masculinizada, criada em tanques-rede com dois níveis proteicos. Tilápias-do-nilo da linhagem Tailandesa (total de 2.400), com peso médio inicial de 127 g, foram distribuídas em delineamento inteiramente casualizado, com quatro tratamentos, em arranjo fatorial 2×2, correspondente aos grupos de tilápias masculinizadas hormonalmente ou não masculinizadas e ao teor proteico na dieta de 28 ou 32% de proteína bruta, com três repetições. Após 115 dias de alimentação, não houve interação entre os fatores quanto a peso final, ganho de peso, conversão alimentar, comprimento final e sobrevivência. Não houve diferença entre os peixes masculinizados hormonalmente e os não masculinizados, quanto a peso final, ganho de peso e sobrevivência, o que mostra a possibilidade de sua produção em tanques-rede, sem a necessidade de masculinização hormonal. A proteína bruta a 32% na dieta possibita melhor desempenho para ambos os grupos. Alterações histológicas no fígado - como o incremento do volume das células, o desarranjo da disposição cordonal e o aumento de vesículas nos hepatócitos - são encontradas nos peixes masculinizados hormonalmente e são mais acentuadas nos peixes alimentados com 32% de proteína bruta na dieta

Evaluation of use effective microorganisms (EM) with different feeding strategies on growth performance, body chemical composition and economic efficiency of monosex Nile tilapia

A factorial trial was conducted to detect the effect of different feeding strategies of supplementation of effective microorganisms (EM) liquid on the growth performance, feed utilization, body chemical composition and economic efficiency of monosex Nile tilapia (Oreochromis niloticus) juveniles. Three experimental treatments were formulated a basal diet without any addition of EM (control; A), a diet supplemented with 2% EM (B), and a diet supplemented with 4% EM (C). All treatments were offered to fish through two different strategies of feeding the meal: 2/3 in the morning and 1/3 in the afternoon or 1/3 in the morning and 2/3 in the afternoon. Each treatment was replicated three times. Juveniles Nile tilapia with an average initial body weight of 3.85 ± 0.22 g (± SE) were randomly stocked at a rate of 90 juveniles per 1.5 m3 tank. Fish growth performance and feed utilization significantly (P ≤ 0.05) increased with increasing EM supplementation and were positively affected by different feeding strategies. Moreover, the economic evaluation showed that there were more benefits by when using the 4% EM diet and feeding 2/3 of daily meal in the morning

تأثير استخدام جرعات مختلفة من السماد الغير عضوي على خصائص المياه و الإنتاجية الأولية و إنتاجية البلطي النيلي في أحواض ترابية

Earthen ponds (surface area 155 m2 each) were used to study the effect of different doses of inorganic fertilizer on water quality and fish production. Each pond was stocked with 150 fish of Nile tilapia; Oreochromis niloticus (25-30 g/fish). The ponds received inorganic fertilizer (20:20:5 NPK) with doses of 0, 20, 40, 60 and 100 kg/acre/month. The obtained results revealed that fertilization had no significant effect on water temperature, dissolved oxygen, pH value, free ammonia water conductivity, nitrate concentration, total hardness, and total alkalinity. Only Secchi disk reading, orthophosphate concentration and total nitrogen were significantly affected by the same treatments. Chlorophyll 'a' content over all the rearing period was increased upon increasing the applied doses and the highest was obtained at the 100 kg/acre/month dose. The production of Nile tilapia is optimum at the 60-kg dose. Data of carcass proximate analyses on fish showed that there were no significant differences in dry matter, while crude protein, total lipids and ash contents were significantly affected by different doses.تمت هذه الدراسة بغرض تقييم استخدام جرعات مختلفة من السماد الغير عضوي(NPK 5/20/20) في أحواض ترابية بالعباسية، تم استزراع 150 سمكة بلطي نيلي (25-30 جم) في كل حوض ويضاف السماد بمعدل صفر و20 و40 و60 و100 كجم للفدان كل شهر. لم تظهر النتائج وجود اختلافات معنوية في درجة الحرارة والأكسجين الشائب ودوجة الأس الهيدروجيني والأمونيا الحرة ودرجة التوصيل الكهربي وتركيز النترات والقاعدية الكلية والعسر الكلي نتيجة تأثير الجرعات المختلفة من السماد المستخدم بينما كانت الاختلافات معنوية في كل من شفافية المياه وتركيز الفوسفات والنتروجين الكلي . كذلك كان الاختلاف معنوي في متوسط محتوى الكلوروفيل (أ) الني بلغ أعلى قيمة عند 100 كجم للفدان كل شهر، كانت أفضل إنتاجية للبلطي النيلي عند استخدام 60 كجم للفدان كل شهر. لذلك ينصح باستخدام 60 كجم للفدان كل شهر من السماد الغير عضوي (NPK 5/20/20) في مزارع البلطي النيلي

Prebiotic effects of dietary xylooligosaccharides on fish gut microbiota, growth, and immunological parameters – a review

Abstract Xylooligosaccharides (XOSs) are increasingly being explored as prebiotics in fish diets; however, their effects and modes of action have not been well evaluated. Reports have shown that dietary XOS has the potential to improve the proliferation of beneficial gut microbes, and their metabolites, and enhance disease resistance in several fish species. In contrast, other studies report no substantial changes in immune and growth parameters compared to control groups. Like all prebiotics, the mode of action of XOS is based on their selective stimulation of beneficial gut microbiota, which will outcompete and prevent pathogen proliferation in the gut, and produce metabolites that modulate host immune responses. The reports of improved growth performance of XOS fed fish may be due improved intestinal microbiome, enhanced glycolysis activity and elevated gastrointestinal enzymatic activities. Dietary XOSs have different effects on fish performance depending on the fish species and the structure of XOSs (degree of XOS polymerization and substitution). Nevertheless, further research is essential to determine the optimal dosage, degree of polymerization, and substitution levels required to improve each fish species' gut health and growth performance. This review highlights the prebiotic effects of XOSs, their mechanism of action, and knowledge gaps.</jats:p