Energy and Protein Requirements of Growing Lambs in Colombian Highlands.

Determining the nutritional requirements of lambs is necessary to formulate balanced rations and contribute to sustainable sheep production systems. However, limited information is available regarding the nutritional requirements of growing lambs in the Colombian highlands. Twenty-two Romney Marsh males were used. Initially, four lambs were slaughtered at 20 kg body weight (BW). The remaining 18 lambs were distributed into two groups, according to BW (light: 20 BW and heavy: 30 kg BW). Lambs were randomly allocated into one of three different nutritional schemes, according to voluntary intake (no restriction, and 25 and 50% restriction). All the animals received a totally mixed ration. When a voluntary-fed lamb gained 10 kg BW, the two other lambs restricted to 25 and 50% were slaughtered and dissected into components to determine protein and gross energy concentration. Energy and protein accumulation were analyzed through regression analysis. The net energy for maintenance was 82.3 kcal/kg BW0.75, while the energy efficiencies for maintenance and gain were 0.72 and 0.29, respectively. Crude protein for maintenance was 1.78 g/kg BW0.75, and the nitrogen efficiencies for maintenance and gain were 0.41 and 0.27, respectively. The maintenance requirement of energy was greater, while protein was similarly related to values reported in the literature; however, the efficiency of energy and protein use was lower in growing lambs. These results suggested that estimating energy and nitrogen requirements for growing lambs must be adjusted in Colombian highland conditions.

Nitrogen Utilization in Goats Consuming Buffelgrass Hay and Molasses-Based Blocks with Incremental Urea Levels.

The use of goats for meat production faces challenges from environmental and nutritional factors. Urea is an affordable non-protein nitrogen source commonly utilized in ruminant nutrition. The objective of this study was to investigate nitrogen utilization in goats fed low-quality hay supplemented with molasses blocks containing urea. Twenty Anglo-Nubian doelings were individually housed in metabolic cages and provided with chopped Buffelgrass (Cenchrus ciliaris) hay ad libitum. Goats were randomly assigned to four urea levels (0, 2, 4, and 6%; n = 5 per treatment) in molasses blocks for a duration of 30 days. A negative nitrogen balance (-2.458 g/day) was observed in doelings consuming blocks without urea, compared with a positive balance (0.895 g/d) for those consuming the 6% urea blocks. Block nitrogen intake significantly increased with urea level, but urea supplementation did not affect dry matter (DM) or neutral detergent fiber (NDFom) intake or digestibility. A minimum crude protein (CP) requirement of 8% for maintenance in doelings consuming low-quality forage with a urea-based supplement was determined through regression analysis between CP intake (% of DM) and N balance (r2 = 0.479; p < 0.002). The value of 8% of CP obtained in this study is similar to several previous studies reported in the literature, but in this case, the increments in CP came exclusively from urea. In this study, increasing the urea content of molasses blocks up to 6% significantly increased nitrogen intake, retention, and balance in goats. These results contribute to a better understanding of nitrogen utilization in goats fed low-quality hay with urea supplementation.

The Effects of Prenatal Diet on Calf Performance and Perspectives for Fetal Programming Studies: A Meta-Analytical Investigation.

This meta-analysis aimed to identify knowledge gaps in the scientific literature on future fetal-programming studies and to investigate the factors that determine the performance of beef cows and their offspring. A dataset composed of 35 publications was used. The prenatal diet, body weight (BW), average daily gain (ADG) during pregnancy, and calf sex were elicited as possible modulators of the beef cows and their offspring performance. Then, the correlations between these variables and the outcomes of interest were investigated. A mixed multiple linear regression procedure was used to evaluate the relationships between the responses and all the possible explanatory variables. A knowledge gap was observed in studies focused on zebu animals, with respect to the offspring sex and the consequences of prenatal nutrition in early pregnancy. The absence of studies considering the possible effects promoted by the interactions between the different stressors' sources during pregnancy was also detected. A regression analysis showed that prenatal diets with higher levels of protein improved the ADG of pregnant beef cows and that heavier cows give birth to heavier calves. Variations in the BW at weaning were related to the BW at birth and calf sex. Therefore, this research reinforces the importance of monitoring the prenatal nutrition of beef cows.

Valores de referencia de proteínas para la población venezolana

Se presenta la revisión de los valores de referencia de proteínas. Se determinó el consumo de la población venezolana según las Encuestas de Seguimiento al Consumo de Alimentos (ESCA) 2010- 2012. La dieta aportó proteínas de buena calidad, combinando alimentos de origen animal y vegetal en relación aproximada de 1:1. Los valores de referencia se calcularon en base a la ingesta proteica segura indicada por WHO/ FAO/ONU 2007, y ajustando el aporte de proteínas según edad, peso y contribución a la fórmula calórica de proteínas para una actividad física ligera. Los valores de referencia de proteínas recomendados como ingesta segura en g/kg/día son: para niñas y niños, menores de 1 año 1,14 a 1,80; de 1 a 3 años 0,90 a 1,14; de 4 a 6 años 0,86 a 0,89; y de 7 a 10 años 0,91 a 0,92. En adolescentes de 12 a 19 años, el promedio es de 0,88 y 1,07 para el sexo masculino y femenino respectivamente. En adultos de 20 a 59 años, se recomienda 0,83 y en adultos mayores de 60 años 1,00 para hombres y mujeres. En embarazadas se recomiendan consumos adicionales de proteínas según el trimestre de gestación. Las embarazadas adolescentes deben consumir 1,2 a 1,7 g/ kg/día adicional al requerimiento normal. En mujeres lactantes, los valores difieren entre los primeros seis meses post-parto y después de seis meses lactando. En esta actualización de 2012 los valores de referencia de proteínas resultaron en general menor a los recomendados en la revisión del año 2000.

Reference values of proteins for the Venezuelan population. This study presents the reference values for protein requirements. The consumption of the Venezuelan population was obtained according to the Food Consumption Monitoring Survey (ESCA) 2010-2012. The diet provided good quality proteins, combining animal and vegetable foods in an approximate ratio of 1:1.The reference values were calculated based on the safe levels of protein intake recommended by WHO/FAO/UN 2007, with an adjustment for protein supply depending on age, weight, and contribution to the caloric formula of proteins for light physical activity. The reference values for protein requirements recommended as safe levels of intake in g/kg/day are 1.14 to 1.80 for males and females less than one-year-old, from 1 to 3 years, 0.90 to 1.14; from 4 to 6 years old, 0.86 to 0.89; and from 7 to 10 years old, 0.91 to 0.92. For adolescents, the average is 0.88 and 1.07 for males and females, respectively. In adults from 20 to 59 years old, 0.83 for men and women is recommended, and for older adults, 1.00 for men and women. In pregnant women, additional consumptions are recommended according to gestation time. Adolescent pregnant women must consume additional 1.2 to 1.7 g/kg/day to normal requirement. In breastfeeding women, the values differ between the first six months postnatal period and after six months of breastfeeding. The reference values for protein in this update were lower than the values of the 2000 version.

Desempenho zootécnico de girinos de rã-touro com diferentes níveis de proteína e energia digestíveis

From the digestibility values of some ingredients, it was proposed diets with different levels of digestible protein and energy, in a 3x3 factorial design for bullfrog tadpoles, aiming at evaluate the zootechnical performance. The experiment was conducted during 60 days with 810 tadpoles from the same spawning distributed into 27 polypropylene boxes at a density of 1 tadpole/L. The experimental design consisted of a factorial arrangement with three levels of digestible protein (27; 31 and 35%) and three levels of digestible energy (2700; 2800 and 2900kcal/kg) with three repetitions. Parameters evaluated at 60 days were weight gain, feed intake, dietary protein intake, feed conversion, protein efficiency rate and survival rate. Results were subjected to analysis of variance and Duncan test (95% accuracy), and presented no interaction between digestible protein and digestible energy for any parameter evaluated. As for the digestible protein, significant differences were detected in the dietary protein intake, and protein efficiency rate, evidencing inefficiency of diets with high protein values. Bullfrog tadpoles should be given diets with 27% digestible protein by having the best result for the protein efficiency rate and for the dietary protein intake, with the lowest value and similar to other levels among evaluated parameters.

A partir dos valores de digestibilidade de alguns ingredientes foram propostas dietas, com diferentes níveis de proteína e energia digestíveis, em esquema fatorial 3 x 3, destinadas a girinos de rã-touro para avaliar o desempenho zootécnico. O experimento, com duração de 60 dias, foi conduzido com 810 girinos, oriundos da mesma desova, distribuídos em 27 caixas de polipropileno, em uma densidade de 1girino/L. O delineamento experimental foi um esquema fatorial com três níveis de proteína digestível (27; 31 e 35%) e três níveis de energia digestível (2.700; 2.800 e 2.900kcal/kg) com três réplicas. Os parâmetros avaliados aos 60 dias foram ganho de peso, consumo da dieta, consumo em proteína da dieta, conversão alimentar, taxa de eficiência proteica e índice de sobrevivência. Os resultados foram submetidos à análise de variância e ao teste de Duncan (95% de precisão). Os resultados encontrados não apresentaram interação entre proteína e energia digestível para nenhum parâmetro avaliado. Em relação à proteína digestível, foram verificadas diferenças nos parâmetros consumo em proteína da dieta e taxa de eficiência proteica (TEP), o que demonstra ineficiência das dietas com altos valores proteicos. Deve-se oferecer aos girinos de rã-touro dietas com 27% de proteína digestível, por apresentarem melhor resultado para taxa de eficiência proteica e para consumo em proteína da dieta.

Optimum dietary crude protein requirement for juvenile cachama Piaractus brachypomus / Exigência ótima de proteína bruta para juvenis de pirapitinga, Piaractus brachypomus

A growth experiment was conducted to determine the optimal dietary protein requirement for juvenile cachama, Piaractus brachypomus. Six semi-purified isoenergetic experimental diets using casein and gelatin as protein sources were formulated to contain graded levels of protein (16, 20, 24, 28, 32 and 36 percent). Fish initially averaging 15.52±0.33g (mean±SD) were randomly distributed into the tanks (500L) as groups of 20 fish and fed to apparent satiation twice daily for 60 days. The results showed that feed consumption, feed conversion ratio, fish weight gain, specific growth rate, protein efficiency ratio and protein productive value were affected by dietary protein level (P<0.05) . No significant differences were observed in proximal composition of carcass (P<0.05) in response to dietary protein. Analysis of dietary protein level x WG with a second order polynomial regression suggested a requirement of 31.6 percent CP for optimum growth.

O presente experimento foi realizado para determinar o requerimento ótimo de proteína em dietas para juvenis de pirapitinga, Piaractus brachypomus. Foram formuladas seis dietas experimentais semi-purificadas, iso-energéticas e com diferentes níveis de proteína (16, 20, 24, 28, 32 e 36 por cento de PB) usando caseína e gelatina como fontes de proteína. Os peixes com peso inicial 15,52±0,33g (média±SD) foram distribuídos aleatoriamente em grupos de 20 animais por tanque; foram alimentados durante 60 dias, duas vezes/dia até aparente saciedade. Os resultados mostraram que o consumo de alimento, taxa de conversão de alimento, ganho de peso, taxa de crescimento específico, taxa de eficiência de proteína e valores produtivos da proteína e da energia foram significativamente afetados pelos níveis de proteína das dietas (P<0,05). Não foram observadas diferenças significativas na composição proximal da carcaça (P<0,05) entre tratamentos. A análise do ganho de peso em função dos níveis de proteína da dieta, realizada utilizando regressão polinomial de segundo grau, deu um requerimento de 31,6 por cento de proteína para ótimo crescimento de juvenis de pirapitinga.

Optimum dietary crude protein requirement for juvenile cachama Piaractus brachypomus

A growth experiment was conducted to determine the optimal dietary protein requirement for juvenile cachama, Piaractus brachypomus. Six semi-purified isoenergetic experimental diets using casein and gelatin as protein sources were formulated to contain graded levels of protein (16, 20, 24, 28, 32 and 36%). Fish initially averaging 15.52±0.33g (mean±SD) were randomly distributed into the tanks (500L) as groups of 20 fish and fed to apparent satiation twice daily for 60 days. The results showed that feed consumption, feed conversion ratio, fish weight gain, specific growth rate, protein efficiency ratio and protein productive value were affected by dietary protein level (P 0.05) . No significant differences were observed in proximal composition of carcass (P 0.05) in response to dietary protein. Analysis of dietary protein level x WG with a second order polynomial regression suggested a requirement of 31.6% CP for optimum growth.

O presente experimento foi realizado para determinar o requerimento ótimo de proteína em dietas para juvenis de pirapitinga, Piaractus brachypomus. Foram formuladas seis dietas experimentais semi-purificadas, iso-energéticas e com diferentes níveis de proteína (16, 20, 24, 28, 32 e 36% de PB) usando caseína e gelatina como fontes de proteína. Os peixes com peso inicial 15,52±0,33g (média±SD) foram distribuídos aleatoriamente em grupos de 20 animais por tanque; foram alimentados durante 60 dias, duas vezes/dia até aparente saciedade. Os resultados mostraram que o consumo de alimento, taxa de conversão de alimento, ganho de peso, taxa de crescimento específico, taxa de eficiência de proteína e valores produtivos da proteína e da energia foram significativamente afetados pelos níveis de proteína das dietas (P 0,05). Não foram observadas diferenças significativas na composição proximal da carcaça (P 0,05) entre tratamentos. A análise do ganho de peso em função dos níveis de proteína da dieta, realizada utilizando regressão polinomial de segundo grau, deu um requerimento de 31,6% de proteína para ótimo crescimento de juvenis de pirapitinga.

Optimum dietary crude protein requirement for juvenile cachama Piaractus brachypomus

A growth experiment was conducted to determine the optimal dietary protein requirement for juvenile cachama, Piaractus brachypomus. Six semi-purified isoenergetic experimental diets using casein and gelatin as protein sources were formulated to contain graded levels of protein (16, 20, 24, 28, 32 and 36%). Fish initially averaging 15.52±0.33g (mean±SD) were randomly distributed into the tanks (500L) as groups of 20 fish and fed to apparent satiation twice daily for 60 days. The results showed that feed consumption, feed conversion ratio, fish weight gain, specific growth rate, protein efficiency ratio and protein productive value were affected by dietary protein level (P 0.05) . No significant differences were observed in proximal composition of carcass (P 0.05) in response to dietary protein. Analysis of dietary protein level x WG with a second order polynomial regression suggested a requirement of 31.6% CP for optimum growth.

O presente experimento foi realizado para determinar o requerimento ótimo de proteína em dietas para juvenis de pirapitinga, Piaractus brachypomus. Foram formuladas seis dietas experimentais semi-purificadas, iso-energéticas e com diferentes níveis de proteína (16, 20, 24, 28, 32 e 36% de PB) usando caseína e gelatina como fontes de proteína. Os peixes com peso inicial 15,52±0,33g (média±SD) foram distribuídos aleatoriamente em grupos de 20 animais por tanque; foram alimentados durante 60 dias, duas vezes/dia até aparente saciedade. Os resultados mostraram que o consumo de alimento, taxa de conversão de alimento, ganho de peso, taxa de crescimento específico, taxa de eficiência de proteína e valores produtivos da proteína e da energia foram significativamente afetados pelos níveis de proteína das dietas (P 0,05). Não foram observadas diferenças significativas na composição proximal da carcaça (P 0,05) entre tratamentos. A análise do ganho de peso em função dos níveis de proteína da dieta, realizada utilizando regressão polinomial de segundo grau, deu um requerimento de 31,6% de proteína para ótimo crescimento de juvenis de pirapitinga.

Necessidades de proteínas para a população idosa: revisão / Protein requirements for the elderly population: review

The aging of a human being is a natural biological process rather thana pathologic one, characterized by a series of morpho-physiologicalbiochemical and psychological changes that take place throughout the liveof human beings. The in? uence of the aging process on the nutritionarequirements is the object of many studies that were carried out in order tdetermine the adequate intake of nutrients to meet the requirements of thhealthy elderly population. Elderly people should intake proteins in suf? cienquantity to reduce the loss of muscle mass related to aging. However, thhigh intake of this nutrient might represent some undesirable effects tthe health of elderly people, due to kidney and liver problems. This papereviews some articles on protein requirements for the elderly and dietarstudies in the elderly population related to protein intake, using the PubMedDatabase, in a search period between 1978 and 2003. The keywords usedwere: amino acids, protein recommendation, metabolism, elderly.

El envejecimiento del ser humano es un proceso biológico natural y no patológico caracterizado por una serie de alteraciones morfofisiológicas, bioquímicas y psíquicas que acontecen en el organismo a lo largo de toda la vida. La influencia del proceso de envejecimiento sobre las necesidades nutricionales es objeto de numerosos estudios conducidos para establecer la ingestión adecuada de nutrientes para una población anciana saludable. La ingestión de proteínas en el adulto mayor debe suplir la pérdida muscular relacionada con la edad, sin embargo su consumo en exceso puede provocar problemas renales y alteraciones hepáticas que son indeseables. Este artículo revisa algunos trabajos sobre las necesidades de proteínas para el adulto mayor utilizando la Base de Dados PubMed, en el período de 1978 a 2003. Las palabras clave utilizadas para La búsqueda fueron: aminoácidos, necesidades proteicas, metabolismo, adulto mayor.

O envelhecimento do ser humano é um processo biológico natural, e não patológico caracterizado por uma série de alterações morfofisiológicas, bioquímicas e psicológicas que ocorrem no organismo ao longo da vida. A influência do processo de envelhecimento sobre as necessidades de nutrientes é objeto de numerosos estudos que têm sido conduzidos para estabelecer a ingestão adequada de nutrientes para suprir as necessidades da população idosa saudável. A ingestão de proteínas do idoso deve ser na quantidade suficiente para diminuir a perda muscular relacionada com a idade, entretanto, o consumo elevado deste nutriente também pode apresentar efeitos indesejáveis à saúde dos idosos, devido a problemas renais e alterações hepáticas. Este artigo revisa alguns trabalhos sobre recomendações de proteínas para idosos e estudos dietéticos, em relação à ingestão de proteínas neste grupo etário, utilizando a Base de Dados PubMed, no período de pesquisa compreendido entre 1978 e 2008. Os unitermos utilizados na pesquisa foram: aminoácidos, recomendações de proteína, metabolismo, idoso.