ABSTRACT: This study evaluated the effects of Acacia mearnsii tannin extract on milk fatty acid profile of dairy ewes and cows. In experiment 1, twenty-four Lacaune ewes received one of the following dietary treatments: control (no tannin extract added to the diet), T30 (30 g tannin extract/kg concentrate), and T40 (40 g extract/kg concentrate). In experiment 2, thirty Jersey cows received either a control diet (no tannin extract added to the diet) or the same diet containing 40 g tannin extract/kg concentrate (T40). Dry matter intake, milk production and milk solids content of ewes and cows were unaffected by tannin supplementation. The cis-9, trans-11 conjugated linoleic acid (CLA) content increased linearly by 21% in milk fat from ewes fed tannin extract, while the C18:2 n-6 (linoleic acid) content tended (P = 0.051) to increase by 13% in cows fed TE. The supplementation with black wattle tannin extract improves the nutritional quality of milk fat of ewes and cows to a small extent, with no adverse effects on performance or gross milk composition.

RESUMO: O objetivo deste trabalho foi avaliar os efeitos da suplementação com extrato tanífero de acácia negra (Acacia mearnsii) sobre o perfil de ácidos graxos no leite de ovelhas e vacas. No experimento 1, vinte e quatro ovelhas Lacaune receberam um dos seguintes tratamentos dietéticos: controle (sem extrato tanífero), T30 (30 g de extrato tanífero/kg concentrado) e T40 (40 g de extrato tanífero/kg concentrado). No experimento 2, trinta vacas Jersey receberam uma dieta controle ou a mesma dieta contendo 40 g de extrato tanífero/kg concentrado (T40). O consumo de matéria seca, a produção de leite e o teor de sólidos do leite das ovelhas e vacas não foram afetados pela suplementação com o extrato tanífero. O teor de ácido linoleico conjugado (CLA) cis-9, trans-11 aumentou em 21% na gordura do leite de ovelhas alimentadas com o extrato tanífero, enquanto o teor de C18:2 n-6 (ácido linoleico) tendeu (P = 0,051) a aumentar em 13% em vacas suplementadas com o extrato. A suplementação com extrato tanífero de acácia negra melhora em pequena escala a qualidade nutricional da gordura do leite de ovelhas e vacas, sem efeitos adversos no desempenho ou na composição bruta do leite.

Ruminant milk is the lead source of conjugated linoleic acid (CLA) in the human diet, with cis-9, trans-11 CLA being the major among all. Small amounts of trans-10, cis-12 CLA are also found in synthetic supplements. Since both isomers are biologically active with potential health benefits, there is great interest in quantifying them for quality control routines. An alternative method for the analysis of the aforementioned CLAs by fast gas chromatography (GC) is discussed in the present study. The fatty acid methyl ester mixture obtained by alkaline catalysis was injected into a GC equipped with a fame ionization detector (FID) and fitted with an ionic liquid SLB-IL111 chromatographic column (15 m × 0.10 mm × 0.08 µm). Separation was achieved in less than 5 min using a 168 °C isotherm run. Both CLA isomers were quantified by using of single point standard addition statistical approach. Results were contested to those obtained using the recommended 100 m long CP-Sil88 capillary column and none evidence of significant differences was found within 95% confidence interval. Therefore, the proposed method could be valuable to focused regulatory routines of large numbers of samples with greater analytical frequency.

Resumo Um dos maiores problemas atuais da população é a deficiência de nutrientes. Estudos indicam que consumidores consideram o preço dos alimentos mais relevante do que os valores nutricionais. Assim, este trabalho objetivou comparar o custo dos nutrientes de alimentos típicos da dieta brasileira, realizando coletas de preços em mercados virtuais e calculando o custo para se atingir 30% das necessidades diárias de um adulto saudável para oito nutrientes. A carne de frango foi a fonte mais barata de proteína. A fibra de cereal teve o menor custo para fibra e ferro. As fontes mais baratas de cálcio foram o Ovomaltine e os lácteos, e o fígado bovino foi o alimento melhor ranqueado para vitamina A. A vitamina C foi o nutriente mais barato na dieta brasileira, e o suco de acerola a fonte mais barata deste nutriente. Os lácteos ocuparam as seis primeiras posições no “ranking” da vitamina D, e nozes e sementes apresentaram o menor custo para vitamina E. Os resultados mostraram que os consumidores brasileiros podem alcançar a ingestão recomendada de nutrientes considerados críticos a um baixo custo por meio da aquisição dos alimentos melhor ranqueados. No entanto, esse ranqueamento deve ser ponderado em função da qualidade do alimento, conforme preconiza o Novo Guia Alimentar para a População Brasileira.

Abstract Nutrient deficiency is one of the major problems of the human population today. Studies indicate that consumers consider that the price of food is more relevant than its nutritional value. Therefore, this work sought to compare the costs of nutrients provided by typical foods found in the Brazilian diet. Food prices available in virtual markets were collected, and the costs to meet 30% of the daily recommendations for a healthy adult were calculated for eight nutrients. Poultry was found to be the cheapest source of protein. Cereal fiber had the lowest cost for both fiber and iron. The cheapest sources of calcium were Ovaltine and dairy products, whereas cow`s liver was the best ranked food for vitamin A. Vitamin C was found to be the cheapest nutrient in the Brazilian diet, with acerola juice being the cheapest source of this nutrient. Dairy products occupied the first six positions in the ranking of vitamin D, while nuts and seeds were the cheapest sources of vitamin E. The results showed that Brazilian consumers can meet the recommended intake of critical nutrients at a low cost through the purchase of the best ranked foods. However, this ranking should be weighted according to the food quality, as recommended in the New Dietary Guidelines for the Brazilian Population.

Resumo Um dos maiores problemas atuais da população é a deficiência de nutrientes. Estudos indicam que consumidores consideram o preço dos alimentos mais relevante do que os valores nutricionais. Assim, este trabalho objetivou comparar o custo dos nutrientes de alimentos típicos da dieta brasileira, realizando coletas de preços em mercados virtuais e calculando o custo para se atingir 30% das necessidades diárias de um adulto saudável para oito nutrientes. A carne de frango foi a fonte mais barata de proteína. A fibra de cereal teve o menor custo para fibra e ferro. As fontes mais baratas de cálcio foram o Ovomaltine e os lácteos, e o fígado bovino foi o alimento melhor ranqueado para vitamina A. A vitamina C foi o nutriente mais barato na dieta brasileira, e o suco de acerola a fonte mais barata deste nutriente. Os lácteos ocuparam as seis primeiras posições no “ranking” da vitamina D, e nozes e sementes apresentaram o menor custo para vitamina E. Os resultados mostraram que os consumidores brasileiros podem alcançar a ingestão recomendada de nutrientes considerados críticos a um baixo custo por meio da aquisição dos alimentos melhor ranqueados. No entanto, esse ranqueamento deve ser ponderado em função da qualidade do alimento, conforme preconiza o Novo Guia Alimentar para a População Brasileira.

Abstract Nutrient deficiency is one of the major problems of the human population today. Studies indicate that consumers consider that the price of food is more relevant than its nutritional value. Therefore, this work sought to compare the costs of nutrients provided by typical foods found in the Brazilian diet. Food prices available in virtual markets were collected, and the costs to meet 30% of the daily recommendations for a healthy adult were calculated for eight nutrients. Poultry was found to be the cheapest source of protein. Cereal fiber had the lowest cost for both fiber and iron. The cheapest sources of calcium were Ovaltine and dairy products, whereas cow`s liver was the best ranked food for vitamin A. Vitamin C was found to be the cheapest nutrient in the Brazilian diet, with acerola juice being the cheapest source of this nutrient. Dairy products occupied the first six positions in the ranking of vitamin D, while nuts and seeds were the cheapest sources of vitamin E. The results showed that Brazilian consumers can meet the recommended intake of critical nutrients at a low cost through the purchase of the best ranked foods. However, this ranking should be weighted according to the food quality, as recommended in the New Dietary Guidelines for the Brazilian Population.

ABSTRACT This study aimed to evaluate the milk fatty acid (FA) composition of unsupplemented dairy cows grazing on elephantgrass (Pennisetum purpureum Schum. cv. Pioneiro) pastures under three grazing management strategies: pre-grazing height of 120 cm with defoliation intensities of 50 and 70% of the initial height (treatments 120/50 and 120/70) and pre-grazing height of 90 cm with defoliation intensity of 70% (treatment 90/70). Treatments were repeated three times in a complete randomized block design. Tester animals were six multiparous Holsteins cows grouped into pairs according to days in milk and milk yield and allocated to blocks. Individual milk samples were collected after the first and second days of grazing (two-day occupation period) and analyzed for FA composition. Milk fat from 120/50 and 90/70 treatments resulted in higher concentrations of C4:0, C6:0, C17:0 anteiso, rumenic acid (RA), vacenic acid (VA), trans-12 C18:1, trans-13/14 C18:1, cis-11 C18:1, cis-12 C18:1, cis-9, trans-12 C18:2, trans-11, cis-15 C18:2, and total polyunsaturated fatty acids. Additionally, both SCD14 (cis-9 14:1/14:0 + cis-9 14:1) and SCDRA (RA/VA + RA) desaturase indices were reduced in milk fat from cows subjected to 120/50 and 90/70 treatments. On average, the milk fat levels of RA and VA observed in our study were greater than those reported in most studies with tropical grass-based diets and similar to levels usually found in cows grazing on temperate pastures. Overall, our results showed that milk with a desirable fatty acid composition is produced by cows grazing on a tropical grass (elephantgrass cv. Pioneiro), with the combination of a pre-grazing height of 120 cm and a defoliation intensity of 50% of the initial height, being a practical management strategy to achieve this goal.

Resumo: O objetivo deste trabalho foi avaliar o perfil de ácidos graxos (AG) do leite de vacas Holandesas x Gir submetidos a dois tipos de manejo de pastejo (períodos de descanso fixo e variável) de pastagem de Urochloa brizantha 'Marandu'. Utilizou-se o delineamento de blocos ao acaso, com duas repetições de área de pastagem (blocos) por tratamento e quatro vacas por bloco. A produção e a composição do leite não foram influenciadas pelas estratégias de pastejo. Não houve efeito dos tratamentos sobre as proporções (g 100 g-1 de AG totais) dos principais AG (palmítico, linoleico e α-linolênico) do pasto, mas suas ingestões (gramas por dia) foram influenciadas pelas diferenças de ingestão de matéria seca da forragem. As concentrações dos AG no plasma e na gordura do leite não foram influenciadas pelos tratamentos. As concentrações dos ácidos rumênico, vacênico, oleico e α-linolênico na gordura do leite variaram de 0,71 a 0,93, 1,40 a 1,50, 19,40 a 19,70 e 0,39 a 0,43 g 100 g-1 de AG totais, respectivamente. As estratégias de pastejo de U.brizantha 'Marandu' não alteram o perfil de ácidos graxos do leite das vacas.

Abstract: The objective of this work was to evaluate the milk fatty acid (FA) profile of Holstein x Gyr cows subjected to two different grazing managements (fixed and variable rest periods) of Urochloa brizantha 'Marandu' pastures. A randomized complete block design was used, with two replicates of pasture areas (blocks) per treatment and four cows per block. Milk production and composition were not affected by grazing strategies. No treatment effects were observed on the proportions (g 100 g-1 of total FA) of the main FAs (palmitic, linoleic, and α-linolenic) of the pasture, but their intakes (grams per day) were affected by differences in forage dry matter intake. The concentrations of FAs in milk plasma and fat were not affected by the treatments. Milk fat contents of rumenic, vaccenic, oleic, and α-linolenic acids varied from 0.71 to 0.93, 1.40 to 1.50, 19.40 to 19.70, and 0.39 to 0.43 g 100 g-1 total FAs, respectively. Grazing strategies of U.brizantha 'Marandu' cause no changes on the milk fatty acid profile of cows.

The objective of this study was to evaluate the economic viability of feeding dairy cows with diets containing different levels of soybean oil. Cows were fed diets based on tropical forage (Pennisetum purpureum Schum) supplemented with different levels of soybean oil (0.0, 1.5, 3.0, and 4.5% of diet DM). The calculations were made considering the prices of the dietary ingredients and the daily consumption of each dietary treatment. The milk quality-based payment was estimated on the bonus paid for milk fat and protein contents according to two systems used by companies of the dairy sector. The economic benefit was calculated as the difference between the income obtained from milk sale and the cost associated with animal feeding. The MOP scenario analysis (most likely - optimistic - pessimistic) was performed on the basis of the real scenario and variations in milk price and inputs observed in season and off-season periods over the years under study. The diet with 1.5% soybean oil had higher economic benefit when compared with those containing 3.0 and 4.5% soybean oil. All the dietary soybean oil levels would result in bonuses for milk protein content (higher than 3.03 and 3.21). Only the control diet showed a positive economic balance. The bonuses paid for milk protein content were insufficient to cover the additional costs associated with the inclusion of soybean oil in the diets, resulting in negative balances for the treatments with 1.5; 3.0 and 4.5% soybean oil, demonstrating the economic non-viability of supplementing diets of lactating cows with soybean oil.