An economical and efficient approach to reduce the impact of P discharge by aquaculture industry is to adjust the P level in fish feeds to the precise nutrient requirement at different growth stages in a digestible nutrient basis. However, P requirement seems to be species specific and affected by several physiological, dietary and environmental factors. Based on the importance of tambaqui (Colossoma macropomum) to Latin American aquaculture, we designed a 63-day trial to evaluate the effect of available P (AP) levels on growth, nutrient digestibility, haematology and blood biochemical parameters, carcass proximate composition and bone mineralization. Quadruplicate groups of tambaqui juveniles (144 AE 2.0 g) were fed five isonitrogenous (278 g kg À1 digestible protein) and isocaloric (13.5 Mj DE kg À1 ) diets containing graded AP levels (3.0, 5.6, 7.5, 9.1 and 11.0 g kg À1 ) following a completely randomized design. Dicalcium phosphate (DCP) was used as the main P source. No mortalities and signs of P deficiency were observed among the dietary treatments. A remarkably high P digestibility was observed in all plantbased diets with a tendency of decreasing P digestibility with the increase in total P levels. Tambaqui seems to be able to grow well without inorganic P supplementation during the trials; however, this species required 7.0 g AP kg À1 diet for proper bone mineralization. P supplementation had a limited effect on haematology and blood biochemistry of tambaqui. Ecological implications of natural feeding habit and evolutionary position of this species are further discussed, and new hypothesis are drawn based on our results.
Based on the importance of tambaqui, Colossoma macropomum, for Latin American aquaculture and the digestibility of minerals for the production of sustainable aquafeeds, we designed a series of trials to determine the apparent digestibility coefficients (ADCs) of phosphorus, calcium, magnesium, manganese, and zinc from six protein sources: soybean meal (SBM), corn gluten meal 60 (CGM60), cottonseed meal 40, fishmeal (FM), poultry byproduct meal (PBM), and meat and bone meal (MBM); four cereal grain products: corn, wheat middlings, broken rice (BR), and rice bran (RB); and dicalcium phosphate (DCP). Considerable variation in the ADCs of minerals was observed among the feed ingredients. In general, CGM60, PBM, and RB tended to show the highest ADC values, while SBM, MBM, DCP, and BR showed the lowest ADC values. ADC‐P was markedly lower in animal protein sources and the phosphate source (DCP), while high P digestibility was observed for plant protein sources and cereal grain products. Interestingly, tambaqui seems to be able to digest and absorb minerals from plant ingredients more efficiently than animal proteins and DCP. In light of the correlation between nutrient levels and the ADCs of minerals, physiological mechanisms that regulate mineral uptake, and the nutritional ecology of the species, we hypothesize that tambaqui are able to digest minerals from plant proteins with high efficiency.
Summary Determining the ingredients and/or digestibility of a diet is one of the most important steps in fish nutrition for accurate diet formulation. Additionally, the use of digestible nutrient data in fish feed formulation can reduce the environmental impact of aquaculture. To properly determine the nutrient digestibility (ADC) of a feed ingredient and/or compound diets, an accurate faeces‐collecting method should be used to provide reliable information on the digestion capacity of a determined species. Thus, a series of two trials were performed aiming to evaluate and standardize a faeces‐collecting method for Colossoma macropomum. Faeces from all groups were collected using one of the methods. In trial 1, two faeces‐collecting methods (sedimentation and dissection) were evaluated using 80 juveniles (170 g average weight) randomly assigned into four 310‐L aquaria. In trial 2, 135 juveniles (300 g average weight) were randomly distributed into nine 310‐L aquaria and fed a control diet (without binder) and diets containing a dietary binder at 0, 2 and 4 g kg−1 diet aiming to test the effect of binder inclusion on the ADC of nutrients. Fish were fed in triplicate groups per diet. Results showed that the dissection method provided the lowest ADC values for dry matter, phosphorus and gross energy. ADC of dry matter tended to decrease up to 5 h (305 min) of faeces immersion and seem to stabilize afterwards. Using 4 g kg−1 of dietary binder tended to reduce the leaching of DM, and no effect was observed on the protein digestibility. Phosphorus was the nutrient most prone to leaching in faeces. Faeces collection within 1 h is recommended in the sedimentation method in C. macropomum digestibility studies; the use of dietary binder at 4 g kg−1 may be a useful approach to reduce nutrient leaching in the faeces.
3. Alunas no curso de Medicina Veterinária da UFG-GO, bolsistas CNPq 4. Professora doutora da PUC-GO 5. Aluno de Especialização em Zootecnia da UFG-GO 6. Pesquisadora convidada. ReSumoEste estudo foi desenvolvido com o intuito de avaliar os custos de produção e receita bruta por unidade de área da criação de tilápia-do-nilo (Oreochromis niloticus) no sistema raceway, em tanques submetidos a diferentes esquemas de troca de água, baseando-se apenas nos custos com ração e alevinos. Utilizaram-se alevinos de tilápia-do-nilo, revertidos para macho, alimentados três vezes ao dia, ad libitum, com ração comercial extrusada. As se-guintes análises econômicas foram realizadas: incidência de custo, receita líquida parcial, receita bruta e custo operacional parcial. O melhor resultado de biomassa encontrado induziu a maior receita líquida parcial observada no tratamento que utilizou maior troca de água (trinta minutos). Neste tratamento, os tanques com 500 L (0,5m 3 ) de água proporcionaram receita líquida parcial média de R$ 50,77, equivalente a R$ 101,54/m 3 , no período de 120 dias.PALAVRAS-CHAVES: Alto fluxo de água, custo de produção, lucratividade, Oreochromis niloticus.
<p>Avaliou-se o efeito de uma solução de amilase produzida por Aspergillus awamori sobre a digestibilidade in vitro da matéria seca (DIVMS) de milho. Foram realizados dois experimentos, onde o primeiro a solução de enzima amilase foi aplicada por pulverização em 24g de milho moído (2 mm) e o segundo a solução de enzima amilase foi aplicado no fluido ruminal. Os tratamentos foram: controle (0 mL de enzima), 5mL (5 mL de enzima) e 10 mL (10 mL de enzima) para cada experimento. Para a coleta de líquido ruminal foi utilizado um bovino de peso aproximado de 380 kg e o ensaio da DIVMS foi obtido usando a técnica de rúmen artificial adaptada. Para os dois experimentos foi adotado o delineamento inteiramente casualizado, em esquema de parcelas subdivididas 3 x 6, com quatro repetições (jarros). As parcelas foram constituídas por milho tratado com três diferentes níveis de enzima e as subparcelas por seis momentos de digestão. Para enzima amilase aplicada no líquido ruminal o resultado de DIVMS para os três tratamentos nos períodos de 3, 6 e 12 horas não diferiram estatisticamente entre si. Entre o tratamento controle e 5 mL houve diferença significativa nos tempos 15’e 1,5 horas. Foi observado maior DIVMS para o tratamento controle, em relação aos 5 mL, com valores de 54,54% e 49,05, e não houve diferença nos tempos 3, 6, 12 e 24 horas (P>0,05). Entre o tratamento controle e o tratamento com 10 mL de enzima não houve diferença no tempo 15’ e 24 horas. A DIVMS do controle foi superior a tratamento 10 mL (28,74% e 10,53% respectivamente). A DIVMS foi superior para o tratamento controle, indicando que os níveis de 5 e 10 mL de enzimas injetados no fluido ruminal não aumentaram a DIVMS (P>0,05). Para amilase aplicada por pulverização em 24g de milho moído, no tempo de 15’, observou-se que o tratamento controle e 5 mL não diferiram estastiticamente (P>0,05). No entanto, o 10 mL de enzima melhorou a DIVMS em 55,54%, quando comparado ao grupo controle. Foi possível concluir que o tratamento com 5 mL de enzima aumentou a DIVMS em tempos de 3 e 24 horas de incubação e com a aplicação de 10 mL de enzima a DIVMS aumentou em todos os tempos de incubação.</p>
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.
hi@scite.ai
10624 S. Eastern Ave., Ste. A-614
Henderson, NV 89052, USA
Copyright © 2024 scite LLC. All rights reserved.
Made with 💙 for researchers
Part of the Research Solutions Family.