Revisão Crítica: Ácidos graxos essenciais na alimentação do camarão

Four types of poly unsaturated fatty acids (PUFA) are essential for all shrimp species, linoleic (LOA, 18:2n-6), alfa-linolenic (ALA, 18:3n-3), eicosapentaenoic (EPA, 20:5n-3) and docosahexaenoic (DHA, 22:6n-3) acids. Moreover, the arachidonic acid (ARA, 20:4n-6), even when present, seems to be, in crustaceans, not so important or yet dispensable. It is relevant knowing that cholesterol as much as PUFA are not well absorbed when not followed by a substantial amount of lecithin, reaching 5% of the ration. The sum of PUFA reaches around 3% of the diet, even varying according to the species, stage and ration type. For Penaeus monodon, a complex mathematic model was formulated in order to describe the relationships between the requirements of the cited PUFA. Industries involved with feed production on this segment must possess its own adaptation for another species. On the other hand, biochemical knowledge on PUFA n-3 series compounds functions are yet very delayed in comparison to the advances on pharmaceutical industry that investigates the n-6 series, with its prevalence in humans. In this review, the term PUFA is generically used to include ALA, LOA, DPA, EPA, ARA and DHA.Quatro tipos de ácidos graxos polinsaturado (PUFA) são essenciais para todas as espécies de camarão, são os ácidos linoleico (LOA, 18: 2n-6) alfa-linolénico (ALA, 18: 3n-3), eicosapentaenóico (EPA, 20: 5n-3 ) e docosahexaenóico (DHA, 22: 6n-3). Além disso, o ácido araquidónico (ARA, 20: 4n-6), mesmo quando presente, parece ser, em crustáceos, pouco importante ou ainda dispensável. É importante saber que os PUFA não são bem absorvidos quando não seguido por uma quantidade substancial de lecitina, atingindo 5% da ração. A soma de PUFA atinge cerca de 3% da dieta, mesmo variando de acordo com o tipo de espécies, estágio e ração. Para Penaeus monodon, um modelo matemático complexo foi formulado de modo a descrever as relações entre os requisitos de a citada PUFA. As indústrias envolvidas com a produção de alimentos desse segmento, devem possuir suas adaptações próprias para outras espécies. Por outro lado, os conhecimentos bioquímicos sobre as funções dos compostos da série n-3 dos PUFA estão ainda muito atrasados, comparado com os avanços da indústria farmacêutica que investiga a série n-6, com prevalência no homem. Nesta revisão, o termo PUFA é genericamente usado para incluir ALA, LOA, DPA, EPA, ARA e DHA

Critical review: cholesterol and fat-soluble vitamins on shrimp feeding

Four types of poly unsaturated fatty acids (PUFA) are essential for all shrimp species, linoleic (LOA, 18:2n-6), alfa-linolenic (ALA, 18:3n-3), eicosapentaenoic (EPA, 20:5n-3) and docosahexaenoic (DHA, 22:6n-3) acids. Moreover, the arachidonic acid (ARA, 20:4n-6), even when present, seems to be, in crustaceans, not so important or yet dispensable. It is relevant knowing that cholesterol as much as PUFA are not well absorbed when not followed by a substantial amount of lecithin, reaching 5% of the ration. The sum of PUFA reaches around 3% of the diet, even varying according to the species, stage and ration type. For Penaeus monodon a complex mathematic model was formulated in order to describe the relationships between the requirements of the cited PUFA. Industries involved with feed production on this segment must possess its own adaptation for another species. On the other hand, biochemical knowledge on PUFA n-3 series compounds functions are yet very delayed in comparison to the advances on pharmaceutical industry that investigates the n-6 series, with its prevalence in humans. In this review, the term PUFA is generically used to include ALA, LOA, DPA, EPA, ARA and DHA.Lipid quality on shrimp nutrition is very important, especially regarding to its content of essential substances. Nutrient intake is instinctively adjusted when animal selects its feeds in the wild. In captivity, it is possible to observe the cholesterol requirement, as in shrimps, as in other crustaceans, since they do not possess the ability to synthesize this indispensable nutrient for animal survival and development. Cholesterol is a relatively small part of the essential lipids for shrimp, and cannot be replaced by phytosteroids. Since cholesterol is the precursor of the ecdisone hormone (which controls molts), it is particularly more necessary during larvae stages. Also, fat-soluble vitamins are vital for shrimp growth. However, vitamins D and K functions are still partially known, because the premises of their functions in vertebrates have no equivalent in crustaceans. In this sense, only the relevance of vitamin E to protect PUFA has an explanation so far. On the other hand, the carotenoid astaxanthin appears to be as effective as an antioxidant that is difficult to justify the need for tocopherol. Dietetic imbalance in essential lipids turns shrimps susceptible to opportunistic infections. This review describes the cholesterol and fat-soluble vitamins importance in shrimp feeding

Low-protein diets on broilers performance reared under different temperatures

O objetivo deste trabalho foi avaliar o desempenho de frangos, entre 42 e 49 dias, alimentados com dietas de baixa proteína e criados em diferentes temperaturas. Foram utilizados 360 frangos, machos, Cobb-500, distribuídos em um delineamento inteiramente ao acaso em esquema fatorial 3x3 (temperatura ambiente de 20, 25 e 32ºC e dietas com teores de proteína bruta de 18,0, 16,5 e 15,0%), com quatro repetições de dez aves cada. As dietas com baixa proteína prejudicaram o desempenho e a eficiência de retenção de nitrogênio dos frangos criados em 32ºC. Os rendimentos de carcaça e de coxa e sobrecoxa foram maiores nas aves criadas a 32ºC. Os demais cortes e a deposição de gordura abdominal não foram alterados. O estresse por calor reduziu o teor de proteína e aumentou o de gordura na coxa e sobrecoxa, ao passo que os teores protéicos não alteraram a composição bromatológica dos cortes. A utilização de dietas com baixa proteína piora o desempenho de frangos, de 42 a 49 dias, criados em estresse por calor. No entanto, essas dietas podem ser utilizadas em frangos criados em 20 ou 25ºC, pois não alteram o desempenho, a qualidade da carcaça e diminuem a excreção de nitrogênio.The objective of this work was to evaluate broilers performance, from 42 to 49 days, fed on low-protein diet and reared under different temperatures. Three hundred and sixty male broilers from Cobb-500 strain were randomly housed in a 3x3 factorial arrangement (environmental temperature of 20, 25 and 32oC and crude protein levels of 18.0, 16.5 and 15.0%) with four replicates of ten birds each. Performance and efficiency of nitrogen retention were impaired in broilers fed on low-protein diets and reared under temperature of 32ºC. Carcass, as well as thigh and drumstick increased in birds reared at hot temperature yield, however other parts yield, and abdominal fat deposition were not altered by the studied factors. Drumstick and thigh protein composition decreased in broilers reared under heat stress, while fat composition increased. Protein levels did not affect carcass composition. Low-protein diet impairs broiler performance in heat-exposed broilers from 42 to 49 days. However, broilers can be fed on low-protein diets under temperatures of 20 or 25ºC, because these temperatures did not affect broilers performance, carcass quality, and they promoted lower nitrogen excretion

Growth curves, body nutrients deposition and determination of protein requirement for light and semi heavy hen pullets

Growth curves of pullets were adjusted to describe the deposition rates of body components and estimate the requirements in protein. Altogether 1500 poultry were randomly distributed in 30 repetitions of 25 birds. The experimental period was divided into four stages (1 to 4 weeks 5 to 11 weeks and 12 to 16 weeks old). The rations formulated based on corn and soybean meal were offered the will. Weekly, pullets were heavy and two birds separates by lineage to be in determining chemical composition of body nutrients. The informations was used to obtain the parameters of the Gompertz model. Allometric relationships were used to describe the changes in body composition in protein, lipid, ash and water in the body gutted and without feathers. The data of body weight growth of the strains pullets Dekalb White and Bovans Goldlina fit to the Gompertz function. The allometric coefficients of fat, water and mineral matter on the basis in proteic weight of the lines Dekalb and Bovans lines were respectively: 0.114 vs 1.160; 0.811 vs 0.429; 0.930 vs 0.189. There are differences among genotypes for growth rates and deposition of body nutrients and fearther. The light-line is earlier. The total protein requirements (maintenance and gain) for pullets of 1 to 4, 5 to 11 and 12 to 16 weeks of age were respectively 4,41; 9,814; 12,612 g / d for Dekalb White and 4.82; 8,859; 7,673g / d to Bovans Goldline. The aim of this work was to determine growth curves and body nutrients deposition by using Gompertz equation, and to estimate protein requirement in light and semi heavy hen pullets. In total, 1,500 hen pullets were distributed at random into 30 repetitions of 25 birds each. Experimental period was divided into three steps (1st to 4th, 5th to 11th and 12th to 16th weeks of age). Rations were formulated based on corn and soybean meal and offered ad libitum. Birds were weighed weekly. Two birds per repetition were used to determine chemical body composition and data were used to obtain Gompertz model parameters. Allometric ratios were used to describe changes in the body composition in protein, lipid, mineral matter and water in the eviscerated and featherless body. Weight-age data of Dekalb White and Bovans Goldline pullets were well described by Gompertz function. Allometric coefficients of fat, water and mineral matter in function of the protein body weight were, respectively: 0.114, 0.811 and 0.930 for Dekalb line and 1.160, 0.429 and 0.189 for Bovans line. There are differences between lines for growth rates and body nutrients and feathers deposition, with Dekalb line being the most precocious. Total protein requirements (maintenance and growth) for pullets from 1st to 4th, 5th to 11th and 12th to 16th weeks of age were 4.41; 9.814 and 12.612 g˙d-1 for Dekalb White and 4.82; 8.859 and 7.673 g˙d-1 for Bovans Goldline, respectively