Primer aislamiento de Escherichia coli no O157 productor de toxina Shiga en carnes bovina y porcina en Venezuela / First isolation of non-O157 shiga toxin producing Escherichia coli in bovine and porcine meats in Venezuela

Escherichia coli productor de toxina Shiga (STEC), es un patógeno transmitido por alimentos. El serotipo O157:H7 se considera clínicamente el más importante, pero un 50% de las infecciones por STEC corresponden a serotipos no O157. En Venezuela, la presencia de cepas STEC no O157 en productos cárnicos no ha sido reportada, lo que motivó este trabajo. Se analizaron 70 muestras de carne molida (35 bovinas y 35 porcinas). El aislamiento de E. coli se llevó a cabo en agar MacConkey sorbitol, suplementado con cefixima y la identificación bioquímica según pautas de la FDA. Se realizó la extracción del ADN y ensayos de PCR para la identificación de cepas STEC O157:H7 y STEC no O157. De 70 muestras analizadas, 50 (71,4%) resultaron positivas al aislamiento de E. coli, lográndose identificar 47 cepas sorbitol positivas y 3 cepas sorbitol negativas. La PCR demostró ausencia de STEC O157:H7 y presencia de STEC no O157 productor de toxina Shiga Stx1 y Stx2 en el 4,3% de las muestras analizadas. Se demuestra, por primera vez en el país, la circulación de cepas STEC no O157 en productos cárnicos, lo que permite sugerir el establecimiento de estrategias de prevención asociadas a este patógeno.

Shiga toxin producing Escherichia coli (STEC) is a food-transmitted pathogen. Serotype O157:H7 is considered the most clinically important, but 50% of STEC infections correspond to non-O157 serotypes. In Venezuela, presence of non-O157 STEC strains in meat products has not been reported, which was the reason for this study. Seventy ground meat samples were analyzed (35 bovine and 35 porcine). E. coli isolation was done in MacConkey sorbitol agar, supplemented with cefixim, and the biochemical identification was done according to FDA guidelines. DNA extraction and PCR assays were used for the identification of STEC O157:H7 and not O157 strains. Of the 70 samples analyzed, 50 (71.4%) were positive for E. coli isolation, and 47 sorbitol positive and 3 sorbitol negative strains were identified. PCR showed absence of STEC O157:H7 and presence of non-O157 STEC Shiga toxin Stx1 and Stx2 producers in 4.3% of the samples analyzed. This is the first time that the circulation of non-O157 STEC strains in meat products is demonstrated in this country, which suggests that prevention strategies associated to this pathogen should be established.

Fontes protéicas vegetais na alimentação da carpa húngara / Plant protein sources on common carp feeding

A substituição parcial da farinha de carne suína por farelos vegetais em dietas para juvenis de carpa húngara (Cyprinus carpio) foi avaliada em cinco dietas experimentais: um controle (farinha de carne suína (FCS) como fonte protéica) e quatro dietas vegetais: farelo de soja (FS), farelo de canola (FC), farelo de girassol (FG) ou farelo de linhaça (FL), substituindo 50 por cento da proteína proveniente da FCS. 195 juvenis (43,4±0,4g) foram alimentados duas vezes ao dia (9 e 15 horas) durante 71 dias. Ao final do experimento, maior peso (205,69g), ganho em peso (2,29g dia-1), taxa de crescimento específico (2,2 por cento dia-1) e conversão alimentar (1,74) foram obtidos nas dietas com FCS, seguido dos tratamentos FC e FS que não diferiram entre si. Os peixes alimentados com FCS, FG e FS apresentaram maior gordura corporal. A dieta FL apresentou piores resultados de desempenho, coeficiente de retenção protéica, deposição de proteína e gordura corporal e no filé. Pode-se concluir que a dieta à base de farinha de carne suína proporciona maior crescimento e deposição de proteína em juvenis de carpa húngara, comparada às dietas com farelos vegetais; os parâmetros de carcaça (rendimentos e índices digestivos) não são afetados pelas fontes protéicas da dieta.

This study was conducted to evaluate the partial replacement of porcine meat meal by plant-protein meals in diets for common carp (Cyprinus carpio). Five experimental diets were evaluated: control (FCS), only porcine meat meal as protein source, and four plant-based diets: soybean meal (FS), canola meal (FC), sunflower meal (FG) or linseed meal (FL) replacing 50 percent of protein from porcine meat meal. Juveniles (195, 43.4±0.4g) were fed twice daily (9:00 am and 03:00pm) for 71 days. At the end of the trial, the best weight (205,69g), weight gain (2,29g day-1), specific growth rate (2,2 percent day-1) and food conversion ratio (1,74) were obtained in FCS, followed by FC and FS, that did not differ among each other. Fish fed FCS, FG and FS showed higher body fat. The FL diet had the worst performance, protein retention coefficient, protein and fat deposition in whole body and fillet. It was concluded that a diet based on porcine meat meal provides higher growth and protein deposition in common carp juveniles, compared to diets with plant-protein meals; carcass parameters (carcass and fillet yield and digestive indices) are not affected by the dietary protein sources.

Determination of soy proteins in calabresa sausage by densitometry on gel electrophoresis

Soy proteins are widely employed in meat products. However addition of non-meat proteins in calabresa sausages is not allowed according to the Brazilian legislation and in case of the non-declared addition of this foreign protein in consumed food, it may trigger allergic reactions in some consumers. Polyacrylamide gel electrophoresis (SDS-PAGE) was used for determining soy proteins in calabresa sausages. Fraud simulations were performed adding different concentrations (0%; 0.5%; 1%; 2%; 5%;10%; 20% and 100%) of soy proteins in sausages. The qualitative analysis was not sensitive to detect thelo west concentrations of soy proteins. On the other hand, by using semi-quantitative analysis by means of densitometry of selected protein fractions from soy and porcine meat, the presence of soy proteins could be determined in the all of analyzed concentrations. This methodology could be implemented, without large investments, for conducting quality control of sausages. (AU)

Determination of soy proteins in calabresa sausage by densitometry on gel electrophoresis

Soy proteins are widely employed in meat products. However addition of non-meat proteins in calabresa sausages is not allowed according to the Brazilian legislation and in case of the non-declared addition of this foreign protein in consumed food, it may trigger allergic reactions in some consumers. Polyacrylamide gel electrophoresis (SDS-PAGE) was used for determining soy proteins in calabresa sausages. Fraud simulations were performed adding different concentrations (0%; 0.5%; 1%; 2%; 5%;10%; 20% and 100%) of soy proteins in sausages. The qualitative analysis was not sensitive to detect thelo west concentrations of soy proteins. On the other hand, by using semi-quantitative analysis by means of densitometry of selected protein fractions from soy and porcine meat, the presence of soy proteins could be determined in the all of analyzed concentrations. This methodology could be implemented, without large investments, for conducting quality control of sausages.

Fontes protéicas vegetais na alimentação da carpa húngara

This study was conducted to evaluate the partial replacement of porcine meat meal by plant-protein meals in diets for common carp (Cyprinus carpio). Five experimental diets were evaluated: control (FCS), only porcine meat meal as protein source, and four plant-based diets: soybean meal (FS), canola meal (FC), sunflower meal (FG) or linseed meal (FL) replacing 50% of protein from porcine meat meal. Juveniles (195, 43.4±0.4g) were fed twice daily (9:00 am and 03:00pm) for 71 days. At the end of the trial, the best weight (205,69g), weight gain (2,29g day-1), specific growth rate (2,2% day-1) and food conversion ratio (1,74) were obtained in FCS, followed by FC and FS, that did not differ among each other. Fish fed FCS, FG and FS showed higher body fat. The FL diet had the worst performance, protein retention coefficient, protein and fat deposition in whole body and fillet. It was concluded that a diet based on porcine meat meal provides higher growth and protein deposition in common carp juveniles, compared to diets with plant-protein meals; carcass parameters (carcass and fillet yield and digestive indices) are not affected by the dietary protein sources.

A substituição parcial da farinha de carne suína por farelos vegetais em dietas para juvenis de carpa húngara (Cyprinus carpio) foi avaliada em cinco dietas experimentais: um controle (farinha de carne suína (FCS) como fonte protéica) e quatro dietas vegetais: farelo de soja (FS), farelo de canola (FC), farelo de girassol (FG) ou farelo de linhaça (FL), substituindo 50% da proteína proveniente da FCS. 195 juvenis (43,4±0,4g) foram alimentados duas vezes ao dia (9 e 15 horas) durante 71 dias. Ao final do experimento, maior peso (205,69g), ganho em peso (2,29g dia-1), taxa de crescimento específico (2,2% dia-1) e conversão alimentar (1,74) foram obtidos nas dietas com FCS, seguido dos tratamentos FC e FS que não diferiram entre si. Os peixes alimentados com FCS, FG e FS apresentaram maior gordura corporal. A dieta FL apresentou piores resultados de desempenho, coeficiente de retenção protéica, deposição de proteína e gordura corporal e no filé. Pode-se concluir que a dieta à base de farinha de carne suína proporciona maior crescimento e deposição de proteína em juvenis de carpa húngara, comparada às dietas com farelos vegetais; os parâmetros de carcaça (rendimentos e índices digestivos) não são afetados pelas fontes protéicas da dieta.

Fontes protéicas vegetais na alimentação da carpa húngara

This study was conducted to evaluate the partial replacement of porcine meat meal by plant-protein meals in diets for common carp (Cyprinus carpio). Five experimental diets were evaluated: control (FCS), only porcine meat meal as protein source, and four plant-based diets: soybean meal (FS), canola meal (FC), sunflower meal (FG) or linseed meal (FL) replacing 50% of protein from porcine meat meal. Juveniles (195, 43.4±0.4g) were fed twice daily (9:00 am and 03:00pm) for 71 days. At the end of the trial, the best weight (205,69g), weight gain (2,29g day-1), specific growth rate (2,2% day-1) and food conversion ratio (1,74) were obtained in FCS, followed by FC and FS, that did not differ among each other. Fish fed FCS, FG and FS showed higher body fat. The FL diet had the worst performance, protein retention coefficient, protein and fat deposition in whole body and fillet. It was concluded that a diet based on porcine meat meal provides higher growth and protein deposition in common carp juveniles, compared to diets with plant-protein meals; carcass parameters (carcass and fillet yield and digestive indices) are not affected by the dietary protein sources.

A substituição parcial da farinha de carne suína por farelos vegetais em dietas para juvenis de carpa húngara (Cyprinus carpio) foi avaliada em cinco dietas experimentais: um controle (farinha de carne suína (FCS) como fonte protéica) e quatro dietas vegetais: farelo de soja (FS), farelo de canola (FC), farelo de girassol (FG) ou farelo de linhaça (FL), substituindo 50% da proteína proveniente da FCS. 195 juvenis (43,4±0,4g) foram alimentados duas vezes ao dia (9 e 15 horas) durante 71 dias. Ao final do experimento, maior peso (205,69g), ganho em peso (2,29g dia-1), taxa de crescimento específico (2,2% dia-1) e conversão alimentar (1,74) foram obtidos nas dietas com FCS, seguido dos tratamentos FC e FS que não diferiram entre si. Os peixes alimentados com FCS, FG e FS apresentaram maior gordura corporal. A dieta FL apresentou piores resultados de desempenho, coeficiente de retenção protéica, deposição de proteína e gordura corporal e no filé. Pode-se concluir que a dieta à base de farinha de carne suína proporciona maior crescimento e deposição de proteína em juvenis de carpa húngara, comparada às dietas com farelos vegetais; os parâmetros de carcaça (rendimentos e índices digestivos) não são afetados pelas fontes protéicas da dieta.

Alimentação de juvenis de carpa capim com dietas à base de farelos vegetais e forragem / Feeding grass carp juveniles with plant-protein diets and forage

Para avaliar o potencial dos ingredientes de origem vegetal como substitutos da farinha de carne suína em dietas para Ctenopharyngodon idella Valenciennes, (1844) (carpa capim), 180 juvenis (15 por tanque) foram criados durante 60 dias em sistema derecirculação de água. Foi avaliada a substituição da farinha de carne suína (FCS) por farelo de canola (FC), farelo de girassol (FG) e a mistura dos farelos de canola e girassol (FCG). As dietas também continham farelo de soja como fonte proteica. O consumo diário deforragem (1,24 a 2,11% do peso vivo) não diferiu entre os tratamentos. Peso final, ganho em peso, taxa de crescimento específico e conversão alimentar aparente não diferiramestatisticamente entre as dietas. O rendimento de filé foi maior nos tratamentos FC e FCG, enquanto o índice digestivossomático foi maior nos tratamentos FG e FCG. Maior teor degordura e menores teores de proteína no peixe inteiro e de cinzas no filé foram obtidos no tratamento FCG. Os filés dos tratamentos FCS e FCG apresentaram maior valor de luminosidade. Os peixes da dieta FCS apresentaram maiores valores de proteínas, triglicerídeos e colesterol total no soro. Conclui-se que os farelos de canola e girassol podem ser utilizados em dietas para recria da carpa capim.

To evaluate the potential of plant-protein sources to replace porcine meat meal in diets for grass carp juveniles, 180 fish (15 per tank) were reared for 60 days in a re-use water system.We evaluated the replacement of porcine meat meal (FCS) for canola meal (FC), sunflower meal (FG) or a mixture of canola and sunflower meal (FCG). The diets were also composed of soybean meal as a protein source. Daily forage intake ranged from 1.24 to 2.11% body weight and did not differ among treatments. Final weight, weight gain, specific growth rate and feed conversion rate did not differ statistically among diets. The fillet yieldwas higher in FC and FCG diets, while the digestive-somatic index was higher in treatments FG and FCG. Higher fat, lower protein content in whole fish and ash in fillet were obtained in the treatment FCG. The FCG and FCS fillets showed higher L value (brightness). Fish fed the FCS diet had higher values of protein, triglycerides and totalcholesterol in serum. We conclude that canola meal and sunflower meal can be used in diets for grass carp in the growing phase.

Alimentação de juvenis de carpa capim com dietas à base de farelos vegetais e forragem / Feeding grass carp juveniles with plant-protein diets and forage

Para avaliar o potencial dos ingredientes de origem vegetal como substitutos da farinha de carne suína em dietas para Ctenopharyngodon idella Valenciennes, (1844) (carpa capim), 180 juvenis (15 por tanque) foram criados durante 60 dias em sistema derecirculação de água. Foi avaliada a substituição da farinha de carne suína (FCS) por farelo de canola (FC), farelo de girassol (FG) e a mistura dos farelos de canola e girassol (FCG). As dietas também continham farelo de soja como fonte proteica. O consumo diário deforragem (1,24 a 2,11% do peso vivo) não diferiu entre os tratamentos. Peso final, ganho em peso, taxa de crescimento específico e conversão alimentar aparente não diferiramestatisticamente entre as dietas. O rendimento de filé foi maior nos tratamentos FC e FCG, enquanto o índice digestivossomático foi maior nos tratamentos FG e FCG. Maior teor degordura e menores teores de proteína no peixe inteiro e de cinzas no filé foram obtidos no tratamento FCG. Os filés dos tratamentos FCS e FCG apresentaram maior valor de luminosidade. Os peixes da dieta FCS apresentaram maiores valores de proteínas, triglicerídeos e colesterol total no soro. Conclui-se que os farelos de canola e girassol podem ser utilizados em dietas para recria da carpa capim. (AU)

To evaluate the potential of plant-protein sources to replace porcine meat meal in diets for grass carp juveniles, 180 fish (15 per tank) were reared for 60 days in a re-use water system.We evaluated the replacement of porcine meat meal (FCS) for canola meal (FC), sunflower meal (FG) or a mixture of canola and sunflower meal (FCG). The diets were also composed of soybean meal as a protein source. Daily forage intake ranged from 1.24 to 2.11% body weight and did not differ among treatments. Final weight, weight gain, specific growth rate and feed conversion rate did not differ statistically among diets. The fillet yieldwas higher in FC and FCG diets, while the digestive-somatic index was higher in treatments FG and FCG. Higher fat, lower protein content in whole fish and ash in fillet were obtained in the treatment FCG. The FCG and FCS fillets showed higher L value (brightness). Fish fed the FCS diet had higher values of protein, triglycerides and totalcholesterol in serum. We conclude that canola meal and sunflower meal can be used in diets for grass carp in the growing phase.