Efficiency of protein combinations in diets for Rhamdia quelen: growth, digestive and metabolic biochemistry and nutrient deposition.

This study was conducted to determine the best combination of protein sources in diets for jundiá, based on growth, metabolism, and nutrient deposition. Five protein combinations were tested: casein + fish meal (control), casein + gelatin, casein + albumin, casein + albumin + fish meal, and albumin + fish meal, in diets containing 370 g Kg-1 of crude protein and 13.4 MJ Kg-1 of digestible energy. The fish (9.38 ± 0.12 g) were allocated in a water recirculation system at a density of 3.35 g L-1 per experimental unit and fed until apparent satiety for 40 days with the diets. The fish fed with the control diet had the highest final weight, specific growth rate, protein and feed efficiency ratio, protein retention, and best apparent feed conversion. On the other hand, fish that received casein + albumin and albumin + fish meal diets showed worse results in growth and body protein retention, low trypsin and chymotrypsin activity, and high intestinal amylase activity. Therefore, the combination referred to as control (casein + fish meal) conclusively provides the best rhythm for nutrient digestion and metabolism processes, enabling fish to reach greater growth and retention of body protein with low whole-fish fat content.

Growth performance, plasma and hepatic biochemistry of jundiá Rhamdia quelen fed dephytinized rice bran protein concentrate.

A 45-day feeding assay was carried out to evaluate the effects of crescent levels of dephytinized rice bran protein concentrate (DRBPC) on growth performance, nutrient deposition, plasma and liver parameters of jundiá Rhamdia quelen. Five experimental diets were formulated with inclusion of 0 (control), 10, 15, 20, and 30% of DRBPC. In total 500 jundiás (initial body weight 6.28 ± 0.12 g) were allocated in 20 tanks (230 L) to give four groups for each treatment. Fish were fed to apparent satiation for 45 days. Weight gain and specific growth rate were evaluated by cubic regression analysis (P < 0.05) and displayed maximal growth on the inclusion level of 25% of DRBPC. The results indicated that fish fed DRBPC15 and DRBPC30 had lower body protein deposition and hepatosomatic index compared to CONTROL diet, respectively. No significant differences (P > 0.05) were assessed in plasma parameters. The alanine aminotransferase activity was higher in fish fed DRBPC30 compared to CONTROL group. The present study has demonstrated that DRBPC displayed significant nutritional quality for the jundiá. Thus, this new ingredient could be included as a protein source in fish for minimizing the use of fish meal.

Improving nutrient availability of defatted rice bran using different phytase sources applied to grass carp (Ctenopharyngodon idella) diet.

In the present study, we evaluated the effects of the hydrolysis of phytate of defatted rice bran (DRB) by a pretreatment with non-commercial phytase produced by Saccharomyces cerevisiae (DRB-PS) compared to the application of Natuphos® (commercial phytase produced by the BASF Company) (DRB-PN) in diets for grass carp, Ctenopharyngodon idella. Fish (57.55 ± 0.4 g) fed one of the experimental diets in triplicates for 35 days. Effects of the phytase used on blood parameters, intestinal proteases and hepatic glucose were not observed (p > 0.05). Similarly, no differences were found for serum phosphorus (P). However, were found higher levels of calcium (9 and 5.25%) in the control treatment in relation to DRB-PS and DRB-PN respectively, besides higher calcium-phosphorus ratio was found in this treatment. For the fish carcass composition was not statistically different (p > 0.05) except total lipids, which showed its highest content in fish fed on the DRB-PN diet (p < 0.05). The obtained results suggested that the use of the phytase, irrespective to its source may eliminate the use of traditional P sources in fish diets.

Sunflower protein concentrate and crambe protein concentrate in diets for silver catfish Rhamdia quelen (Quoy and Gaimard, 1824): use as sustainable ingredients.

The objective of this study was to evaluate growth and metabolic parameters of silver catfish fed with protein concentrates of sunflower meal (SMPC) and crambe meal (CrMPC). The study evaluated two levels of substitution, where 25 or 50% of animal protein was replaced with plant-based protein. A total of 300 silver catfish (14 ± 0.26 g) were used in five treatments and three replications, in fifteen 280-liter experimental units. The results were submitted to analysis of variance and the means of the control diet was compared to the remaining treatments by Dunnett's test at 5% significance level. At the end of the trial, no differences were observed for the variables final weight and daily weight gain. However, minor feed conversion was observed in the groups Control and SMPC-25%. Metabolic parameters were analyzed in the plasma and liver, where no significant differences were found for any of the blood parameters analyzed. In the analyzed liver parameters (ammonia, protein, amino acids and ALAT), the liver protein content was lower in fish consuming SMPC-50%, CrMPC-50% and 25% CrMPC diets. The amino acids content was higher in fish receiving the SMPC-25% diet. It can be concluded that sunflower meal protein concentrate is better utilized by fish and more efficient metabolically than crambe meal. This study demonstrated that a newly developed protein concentrate SMPC and CrMPC can effectively replace 25% and 50% the animal protein in a diet free of FM.

Crambe (Crambe abyssinica) and sunflower (Helianthus annuus) protein concentrates: production methods and nutritional properties for use in fish feed.

The purpose of this study was to develop and improve protein concentration techniques for two industrial by-products with the potential for use in fish feed. In particular, we chemically characterized crambe meal and sunflower meal and their protein concentrates. Three different protein concentration methods were tested: isoelectric pH (pHi), acid pH and alkaline pH. For crambe and sunflower meals extraction using the pHi method was most efficient in terms of protein yield and crude protein content in the concentrates; this method also increased lysine and methionine content in the concentrates. The water holding capacity of the sunflower protein concentrate was greater than that of the crambe protein concentrate. The crambe protein concentrate had a foam-formation capacity of 15%, which stabilized at 6% after 90 minutes. The protein concentration method also reduced total phenolic content by approximately 50% in the concentrates compared with the meals. Therefore, we conclude that protein concentration using the pHi method is the most efficient technique for crambe and sunflower meals, and the use of this technique can decrease total phenolic compounds while improving meal quality for fish feeding.

Crambe (Crambe abyssinica) and sunflower (Helianthus annuus) protein concentrates: production methods and nutritional properties for use in fish feed

ABSTRACT The purpose of this study was to develop and improve protein concentration techniques for two industrial by-products with the potential for use in fish feed. In particular, we chemically characterized crambe meal and sunflower meal and their protein concentrates. Three different protein concentration methods were tested: isoelectric pH (pHi), acid pH and alkaline pH. For crambe and sunflower meals extraction using the pHi method was most efficient in terms of protein yield and crude protein content in the concentrates; this method also increased lysine and methionine content in the concentrates. The water holding capacity of the sunflower protein concentrate was greater than that of the crambe protein concentrate. The crambe protein concentrate had a foam-formation capacity of 15%, which stabilized at 6% after 90 minutes. The protein concentration method also reduced total phenolic content by approximately 50% in the concentrates compared with the meals. Therefore, we conclude that protein concentration using the pHi method is the most efficient technique for crambe and sunflower meals, and the use of this technique can decrease total phenolic compounds while improving meal quality for fish feeding.

Lysine from cooked white rice consumed by healthy young men is highly metabolically available when assessed using the indicator amino acid oxidation technique.

Cooked white rice (CWR) provides up to 71% of the dietary protein for many people worldwide. The protein digestibility-corrected amino acid (AA) score is the method adopted by FAO/WHO to evaluate protein quality. Our group has proposed the metabolic availability (MA) of AAs as another determinant of protein quality. It measures the percentage of an indispensable AA that is incorporated during protein synthesis. This study is the first to our knowledge to assess the MA of l-lysine (L-Lys) from CWR in humans using the indicator AA oxidation (IAAO) technique. Three amounts of L-Lys, 10, 15, and 19 mg · kg(-1) · d(-1) (= 28.5, 42.8, and 54.3% of the mean L-Lys requirement of 35 mg · kg(-1) · d(-1)), were studied in 5 healthy young men in a repeated-measures design. To test the principle that the Maillard reaction has an effect on the MA of LLys, we also assessed the MA of L-Lys in oven-browned, cooked rice (n = 3) in the amount of 19 mg · kg(-1) · d(-1) L-Lys. The MA of L-Lys was estimated by comparing the IAAO response with varying L-Lys intakes in rice compared with the IAAO response to varying l-Lys intakes in the reference protein (crystalline AA mixture patterned after egg protein) using the slope ratio method. The MA of L-Lys from CWR was high (97%), but the effect of the Maillard reaction reduced it to 70%. The results show that despite its relatively low content in rice, L-Lys has a high MA when the rice is cooked without being browned.

Supplementation with fiber-rich multimixtures yields a higher dietary concentration and apparent absorption of minerals in rats.

Multimixtures (MMs) are dietary supplements prepared with low-cost ingredients and food by-products that are widely used in various countries to counteract malnutrition. Although MMs have a high content of minerals, they also contain high levels of dietary fiber and associated compounds, which might bind minerals and impair their absorption. In this study, we investigated the hypothesis that the increased dietary fiber content of MMs would impair gastrointestinal mineral absorption due to the metal-binding capacity of dietary fiber. Thus, the objective of the present study was to feed growing rats with a basal diet, representative of a nutritionally deficient diet, alone or supplemented with a low dietary fiber level MM, intermediate dietary fiber level MM, or high dietary fiber level MM (HF) to evaluate the apparent absorption of calcium, phosphorus, magnesium, manganese, and copper. The relative apparent calcium absorption was slightly decreased by the HF addition, with no change in the absolute apparent absorption. The absolute apparent absorption of phosphorus and magnesium was increased by the intermediate dietary fiber level MM and HF additions, whereas the manganese absorption was increased only by the HF addition. The apparent absorption of copper was not affected by the MM supplementation. The increased apparent absorption of minerals was always related to the increase in the mineral dietary concentration triggered by the MM. Thus, we concluded that the increased dietary fiber levels in the MMs increased the mineral levels, and MMs with intermediate and high fiber levels may be used to improve the mineral balance of poor diets.

Resposta biológica de ratos ao amido resistente / Biological response of rats to resistant starch

O amido resistente (AR) vem sendo intensamente pesquisado nos últimos anos em função de seus efeitos benéficos, como redução da energia da dieta, aumento da produção de fezes e desenvolvimento de microrganismos benéficos no trato intestinal, entre outros. O objetivo deste trabalho foi avaliar a influência do AR da dieta sobre alguns parâmetros de resposta biológica. Foram utilizados ratos machos Wistar (97,1±5,3g) alimentados com rações experimentais suplementadas com 0, 3, 9 e 18% de AR. Os animais foram submetidos a um período de adaptação de 5 dias e, durante o período experimental (15 dias), foramo btidos dados e amostras para a determinação do consumo, ganho de peso, digestibilidade aparente da matéria seca e do amido, produção de fezes úmidas e secas, umidade, pH e nitrogênio nas fezes. A adição de AR às rações não influenciou o consumo, mas diminuiu significativamente o peso dos animais. A produção de fezes úmidas e secas foi significativamente maior em níveis de 9 e 18% de AR. O consumo de AR também aumentou significativamente o teor de umidade e de nitrogênio nas fezes, bem como diminuiuo pH fecal. Os efeitos observados neste trabalho podem ser essencialmente atribuídos à menor digestibilidade aparente do amido e a sua fermentação pela microflora intestinal, o que demonstra seu efeito benéfico no auxílio à manutenção da saúde