IMPROVING THE UNDERSTANDING OF DIFFERENT DIETS ON THE CONCENTRATION AND METABOLISM OF THE MAMMALIAN LIGNAN ENTEROLACTONE IN DAIRY CATTLE

Flaxseed (Linum usitatissimum) is the richest source of the plant lignan secoisolariciresinol diglucoside (SDG), which is precursor for the synthesis of the mammalian lignans enterolactone (EL) and enterodiol (ED) by the gastrointestinal microbes in mammals. There is a great deal of interest in promoting increased intakes of lignans in humans’ diet due to their potential health benefits, especially in the prevention of cardiovascular diseases, hypercholesterolaemia, breast and prostate cancers, and osteoporosis. Consumption of milk and dairy products enriched in EL could be an excellent strategy to increase the intake of lignans by humans. The first (Chapter II) and second (Chapter III) studies presented in this dissertation aimed to evaluate strategies to improve the concentration of EL in milk of dairy cows. In Chapter II, we evaluated the effects of replacing ground corn (GRC) with incremental amounts of liquid molasses (LM) on production, milk composition (fat, true protein, lactose, EL, urea N, fatty acids), plasma concentrations of antioxidant enzymes and urea N, and apparent total-tract digestibility of nutrients in Jersey cows fed FM. Sixteen multiparous organically-certified Jersey cows averaging (means ± standard deviation) 99 ± 41 d in milk and 462 ± 38 kg of body weight were randomly assigned to treatment sequences in a replicated 4 × 4 Latin square design with 14 d for diet adaptation and 7 d for data and sample collection. Diets were fed as total mixed rations and consisted (dry matter basis) of 52% grass-legume baleage, 8% grass hay, 8.5% soyhulls, 2.5% roasted soybean, and 15% FM. Ground corn was totally replaced by increasing amounts of LM at 0, 4, 8, or 12% of the diet dry matter. Orthogonal polynomials were used to test linear, quadratic, and cubic effects in response to LM supplementation using the MIXED procedure of SAS. Milk concentration of EL tended to respond cubically when replacing GRC by incremental amounts of LM in cows fed FM. The plasma activities of the antioxidant enzymes glutathione peroxidase and catalase did not differ, but superoxide dismutase activity tended to respond cubically with feeding increasing amounts of LM at expense of GRC. Dry matter intake and yields of milk and milk fat, true protein, and lactose decreased linearly with substituting GRC for LM. Whereas the concentrations of milk fat and milk true protein did not differ across treatments, milk lactose content decreased linearly. Feeding incremental levels of LM reduced linearly the milk concentration of urea N and the amount of N excreted in urine, and tended to decrease linearly the concentration of plasma urea N. Apparent total-tract digestibilities of dry matter, organic matter, and neutral and acid detergent fiber did not differ across treatments, while digestibility of crude protein decreased linearly. Milk fatty acids profile was substantially changed most notably by linear increases in cis-9, trans-11 18:2, cis-9, cis-12, cis-15 18:3, Σ odd-chain fatty acids, and the trans-11/trans-10 ratio, and linear decreases in cis-9 18:1 and cis-9, cis-12 18:2 when replacing GRC for incremental amounts of LM. In Chapter III was evaluated the effects of feeding flaxseed oil or sucrose alone or in combination on production, milk composition (fat, true protein, lactose, EL, urea N) plasma concentrations of thiobarbituric acid reactive substances (TBARS) and urea N, and apparent total-tract digestibility of nutrients in Holstein cows fed FM. Sixteen multiparous (4 ruminally-cannulated) Holstein cows averaging 94 ± 37.6 d in milk and 680 ± 79.1 kg of BW at the beginning of the study were used. Cows were randomly assigned to treatment sequences in a 4 replicated 4 × 4 Latin square design. Each experimental period lasted 25 d with 18 d for diet adaptation and 7 d for data and sample collection. Treatments were fed (dry matter basis) as total-mixed rations consisting of a 60:40 forage-to-concentrate ratio and included: a negative control diet (-CTRL; 8% SBM plus 23% ground corn); 15% FM +10.7% ground corn + 5% sucrose (SUCR); 15% FM + 15.4% ground corn + 3% flaxseed oil (OIL); and 15% FM +10.2% ground corn + 5% sucrose + 3% FO (COMBO). It was observed that cows fed FM had lower dry matter intake (DMI) compared with that fed soybean meal. Within cows fed FM, the reduction in DMI was greatest in cows fed the OIL diet with no difference between SUCR and COMBO treatments. Milk yield did not differ between cows fed the -CTRL diet and those fed the SUCR and OIL diets. However, a negative associative effect was observed for milk production when FM was supplemented with sucrose and FO. The concentration and yield of milk fat decreased when FO was added to FM. No effects of treatments were observed regarding concentrations and yield of milk true protein, and concentration of milk lactose. However, lactose yield and MUN tended to decrease in the COMBO diet. Digestibility of DM and OM were lower in cows fed FM diets than in those offered the –CRTL treatment. Digestibility of ADF was greatest in –CRTL, intermediate in SUCR, and lowest in OIL and COMBO and no differences across treatments were observed for the apparent total-tract digestibilities of NDF and CP. As expected, the concentration and yield of milk EL were both greater in cows fed FM diets than those fed soybean meal. No difference in milk EL was observed when FM was supplemented with either sucrose or FO alone or their combination (COMBO diet), suggesting no synergistic effects of sucrose and FO in the conversion of SDG to EL in the rumen. A second aim of this dissertation (Chapter IV) was to determine the pharmacokinetics of EL in newborn dairy calves fed milk replacer (MR) or EL-enriched milk. In newborn calves, suckling stimulates the reflex closure of the esophageal groove so that milk or milk replacer bypass the reticulo-rumen down to the abomasum. Thus, calves may be used as a model to make inferences about the pharmacokinetics of EL in simple-stomach mammals including humans. The objective of this study was to determine the pharmacokinetics of EL from MR or EL-enriched milk consumed by newborn Holstein calves. Twenty Holsteins calves (n = 10 males and 10 females) were used from birth to d 7 of life. The 10 calves born from multiparous cows received 4 L of colostrum using nipple bottles. Whereas, the 10 calves born from primiparous cows were fed 4 L of stored colostrum from multiparous cows when available or colostrum replacer. On d 5 of life, calves were administered 2 L of milk replacer (n = 10; Low-EL treatment: 123 nmol/L EL) or 2 L of EL-enriched milk (n = 10; High-EL treatment: 481 nmol/L EL) during the morning feeding (0700 h). Blood samples were taken from the jugular vein before (0 h) and at 0.5, 1, 1.5, 2, 2.5, 3, 4, 6, 8, 10, 12, 24, and 48 h after oral administration of treatments. The area under the curve for the plasma concentration of EL was analyzed according to the trapezoidal rule between 0 and 12 h after treatment administration, and it was greater in High- (26 nmol/L × h) than Low-EL calves (4.30 nmol/L × h). Similarly, the maximum concentration of EL in plasma was greater in High- (5.06 nmol/L) vs. Low-EL calves (1.95 nmol/L). Furthermore, the time after treatment intake to reach maximum plasma concentration of EL was faster in High- (4.31 h) compared with Low-EL (4.44 h) treatment. Calves were able to absorb EL, thus indicating that EL-enriched milk can be potentially used as source of EL to pre-weaned ruminants

FLAXSEED MEAL FEEDING TO DAIRY COWS AS A STRATEGY TO IMPROVE MILK ENTEROLACTONE CONCENTRATION: A LITERATURE REVIEW

ABSTRACT: Flaxseed (Linum usitatissimum) is the richest source of the plant lignan secoisolariciresinol diglucoside (SDG). In mammals, including bovine, SDG is converted to the mammalian lignans enterolactone (EL) and enterodiol (ED) by the action of gastrointestinal microbes. There is a great deal of interest in promoting increased intakes of lignans in humans’ diet due to the potential health benefits of mammalian lignans, especially in the prevention of cardiovascular diseases, hypercholesterolaemia, breast and prostate cancers, and osteoporosis. Consumption of milk and dairy products enriched in EL could be an excellent strategy to increase the intake of lignans by humans. This literature review will focus on presenting feeding strategies capable to improve milk enterolactone concentration. Research has demonstrated the potential of flaxseed meal (FM) feeding to dairy cows as a strategy to improve milk EL concentration, therefore enhancing milk nutraceutical proprieties. A considerable number of studies have demonstrated that feeding vegetable lignans-rich sources, such as FM, to dairy cows improves EL in milk. Additionally, it has been reported that changes in the carbohydrate profile of FM-based diets fed to dairy cows can alter the output of milk EL. The application of animal nutrition as a tool to increase nutraceutical properties of milk (i.e. increased EL concentration) is a valuable strategy for promoting the association of milk with humans’ health benefits and is of great interest in contemporary society. Keywords: nutraceutical proprieties, bioactive compounds, lignans, dairy cows, disease risk reductionO farelo de linhaça na dieta de vacas leiteiras como estratégia para aumentar a concentração de enterolactona no leite: revisão de literatura   RESUMO: A linhaça (Linum usitatissimum) é a principal fonte da lignana vegetal secoisolariciresinol diglucosídeo (SDG). Em mamíferos, incluindo bovinos, SDG é precursor para a síntese das lignanas de mamíferos enterolactona (EL) e enterodiol (ED) pelos microrganismos gastrointestinais. Existe um grande interesse em promover o aumento da ingestão de lignanas na dieta humana devido aos potenciais benefícios da EL a saúde, incluindo principalmente a prevenção de doenças cardiovasculares, hipercolesterolemia, câncer de mama e de próstata e osteoporose. Assim, objetivou-se fazer uma revisão de literatura sobre estratégias de alimentação capazes de melhorar a concentração de enterolactona no leite, melhorando assim a atividade biológica e os benefícios do leite para a saúde humana.fontes ricas em lignanas vegetais, como o farelo de linhaça (FM), aumenta a concentração de EL no leite. Além disso, estudos têm demonstrado que mudanças no perfil de carboidratos de dietas à base de FM fornecidas a vacas leiteiras alteram a concentração de EL do leite. A aplicação da nutrição animal como ferramenta para aumentar as propriedades nutracêuticas do leite (ex. aumentar a concentração de EL) é uma estratégia valiosa para promover a associação do leite com benefícios à saúde humana e é de grande interesse na sociedade moderna. Palavras-chave: propriedades nutracêuticas do leite; compostos bioativos; lignanas; redução do risco de doenças; bovinocultura leiteira.   ABSTRACT: Flaxseed (Linum usitatissimum) is the richest source of the plant lignan secoisolariciresinol diglucoside (SDG). In mammals, including bovine, SDG is converted to the mammalian lignans enterolactone (EL) and enterodiol (ED) by the action of gastrointestinal microbes. There is a great deal of interest in promoting increased intakes of lignans in humans’ diet due to the potential health benefits of mammalian lignans, especially in the prevention of cardiovascular diseases, hypercholesterolaemia, breast and prostate cancers, and osteoporosis. Consumption of milk and dairy products enriched in EL could be an excellent strategy to increase the intake of lignans by humans. This literature review will focus on presenting feeding strategies capable to improve milk enterolactone concentration. Research has demonstrated the potential of flaxseed meal (FM) feeding to dairy cows as a strategy to improve milk EL concentration, therefore enhancing milk nutraceutical proprieties. A considerable number of studies have demonstrated that feeding vegetable lignans-rich sources, such as FM, to dairy cows improves EL in milk. Additionally, it has been reported that changes in the carbohydrate profile of FM-based diets fed to dairy cows can alter the output of milk EL. The application of animal nutrition as a tool to increase nutraceutical properties of milk (i.e. increased EL concentration) is a valuable strategy for promoting the association of milk with humans’ health benefits and is of great interest in contemporary society. Keywords: milk nutraceutical proprieties; bioactive compounds; lignans; disease risk reduction; dairy cattle production.

Concentrate levels for crossbred cows grazing, during the rainy season

O aumento do nível de suplemento concentrado possibilita aumentar o consumo de matéria seca e consequentemente, o desempenho de vacas leiteiras em pastejo. Desta forma, investigaram-se os efeitos de níveis de concentrado sobre a eficiência de utilização da dieta e desempenho de vacas mestiças em pastejo (pasto de Brachiaria brizantha cv Marandu), no período das águas. Utilizaram-se oito vacas mestiças Holandês:Zebu, após o pico de lactação (peso corporal de 495 ± 54 kg e produção inicial média de 13,2 ± 2,4 kg/dia de leite), distribuídas em dois quadrados latinos 4 x 4, de acordo com a produção de leite. Os períodos experimentais tiveram duração de 14 dias cada, sendo os sete primeiros dias para adaptação e os demais para coleta de dados. Avaliaram-se quatro níveis de suplementação concentrada: 0,6; 1,2; 2,4 e 4,8 kg/vaca/dia (base da matéria natural), com 25% de proteína bruta na matéria seca, à base de milho e farelo de soja (60:40), fornecida durante as duas ordenhas diárias. O aumento do nível de concentrado não afetou o consumo de matéria seca total (P=0,157), o que indica taxa de substituição de, aproximadamente, 1:1. A digestibilidade dos componentes da dieta aumentou com o aumento do nível de concentrado, com exceção da digestibilidade da FDNcp, que não foi influenciada (P=0,968). Apesar da maior digestibilidade dos componentes da dieta (exceto FDNcp) não houve efeito do aumento do nível de concentrado sobre o consumo de matéria orgânica digestível. Da mesma forma, a excreção urinária de alantoína e de ácido úrico não foi afetada pelo aumento do concentrado na dieta. O aumento do nível de concentrado não afetou a produção de leite (P=0,5162). Entretanto, o teor de proteína no leite aumentou linearmente (P=0,0056) e o teor de gordura diminuiu linearmente (P=0,0188) com o aumento da suplementação concentrada. Vacas mestiças no terço médio de lactação, em pastagem no período das águas tem seu potencial produtivo alcançado com a utilização de 0,6 kg/dia de suplemento concentrado, não sendo necessário maior nível de suplemento.It was investigated the effects of adding increasing levels of concentrate on efficiency of use of the diet and performance of crossbred cows on pasture (pasture of Brachiaria brizantha cv Marandu) during the rainy season. Eight crossbred Holstein:Zebu cows after peak lactation (body weight 495 ± 54 kg and average initial production of 13.2 ± 2.4 kg/day of milk) were used, being divided into two 4x4 Latin squares, according to milk production. The experiment period lasted 14 days each, with the first seven days for adaptation and the other for data collection. Four levels of concentrate supplementation were evaluated: 0.6, 1.2, 2.4, and 4.8 kg/cow/day (as fed basis) with 25% crude protein in dry matter, based on corn and soybean meal (60:40), provided during the two daily milkings. The increased level of concentrate did not affect dry matter intake (P=0.157), indicating substitution rate of approximately 1:1. Nutrient digestibility increased with increasing level of concentrate, except that NDF digestibility was not affected (P=0.968). Spite of higher nutrient digestibility (except NDF) there was no effect on the consumption of digestible organic matter intake. Likewise urinary excretion of allantoin and uric acid was not different at different levels of concentrate. Milk production was not affected by increasing concentrate; however, the protein content in the milk increased linearly (P=0.0056) and fat content decreased linearly (P=0.0188) with increasing concentrate supplementation. Crossbred cows in mid lactation on pasture during the rainy season reached its production potential with the use of 0.6 kg/day of concentrate supplement, not requiring higher levels of supplementation.Conselho Nacional de Desenvolvimento Científico e Tecnológic

Ureia de liberação lenta em dietas à base de cana-de-açúcar para vacas mestiças Holandês-Zebu

Objetivou-se determinar a inclusão do melhor nível de ureia de liberação lenta (ULL; 0,04; 0,08; 0,16 e 0,32 kg vaca-1 dia-1) em dietas à base de cana-de-açúcar, avaliando o desempenho produtivo de vacas leiteiras mestiças. Utilizaram-se oito vacas multíparas, com peso corporal médio inicial de 448 ± 74 kg. Os animais foram distribuídos em dois quadrados latinos 4x4, com quatro períodos de 14 dias cada (sete dias de adaptação e sete dias de coleta de amostras). Não houve efeito do nível de ureia de liberação lenta (ULL) sobre o consumo de matéria seca, fibra em detergente neutro e extrato etéreo. Porém, o consumo de proteína bruta aumentou linearmente com o fornecimento de ULL. A produção de leite aumentou 0,396 kg de leite para cada 0,1 kg de ULL (3,96 g de leite 1,0 g-1 de ULL). A produção de leite corrigida para 3,5% de gordura e os teores de gordura, proteína, lactose e extrato seco total e desengordurado do leite não foram influenciados pelos níveis de ULL. Recomenda-se fornecer 320 g de ULL vaca-1 dia-1 em dietas à base de cana-de-açúcar e fubá de milho para vacas leiteiras

Ureia de liberação lenta em dietas à base de cana-de-açúcar para vacas mestiças Holandês-Zebu

Objetivou-se determinar a inclusão do melhor nível de ureia de liberação lenta (ULL; 0,04; 0,08; 0,16 e 0,32 kg vaca -1 dia -1 ) em dietas à base de cana-de-açúcar, avaliando o desempenho produtivo de vacas leiteiras mestiças. Utilizaram-se oito vacas multíparas, com peso corporal médio inicial de 448 ± 74 kg. Os animais foram distribuídos em dois quadrados latinos 4x4, com quatro períodos de 14 dias cada (sete dias de adaptação e sete dias de coleta de amostras). Não houve efeito do nível de ureia de liberação lenta (ULL) sobre o consumo de matéria seca, fibra em detergente neutro e extrato etéreo. Porém, o consumo de proteína bruta aumentou linearmente com o fornecimento de ULL. A produção de leite aumentou 0,396 kg de leite para cada 0,1 kg de ULL (3,96 g de leite 1,0 g -1 de ULL). A produção de leite corrigida para 3,5% de gordura e os teores de gordura, proteína, lactose e extrato seco total e desengordurado do leite não foram influenciados pelos níveis de ULL. Recomenda-se fornecer 320 g de ULL vaca -1 dia -1 em dietas à base de cana-de-açúcar e fubá de milho para vacas leiteiras.The aim of this study was to evaluate four levels of slow release urea (SRU; 0.40, 0.80, 0.160 and 0.320 kg day -1 cow -1 ) on performance of crossbred dairy Holstein-Zebu cows fed sugarcane based diets. Eight crossbred Holstein-Zebu cows, third or fourth parity, body weight 448 ± 74 kg in the beginning of first period, were fed sugarcane based diets. The animals were distributed in two 4x4 Latin squares, in four periods of 14 days (samples collected on lasting 7 days of with period). The treatments does not affect the dry matter intake, natural detergent fiber and ether extract. However, the crude protein of diets increase linearly with inclusion of SRU. The milk production increase 0.396 kg of milk for 0.1 kg of SRU (3.96 g of milk1.0 g -1 of SRU), without effect on milk production corrected to 3.5% fat and levels of milk fat, milk protein, milk lactose and milk total solids and non-solids fat from the level levels of SRU. This would suggest supply crossbred Holtein-Zebu by feed sugar cane and corn ground with 320 g day -1 cow -1 SRU

Produção de leite em função de níveis de suplementação com concentrados para vacas leiteiras pastejando capim-elefante

This study aimed to evaluate the effects of supplement amount on milk production and composition. Eight crossbred Holstein-Zebu cows (517±40 kg) were allotted in two 4 x 4 Latin squares, in four periods of 14 days. The experiment was conducted on pasture of Elephant grass (Pennisetum purpureum, Schum) in the rainy season, and the treatments included a control (mineral mixture) and supplement with 24% CP in dry matter at levels of 1.25, 2.5, and 5.0 kg/animal/day, based on corn meal, soybean meal, urea and mineral mixture. The experiment was analyzed as Latin square design including effects of treatment, Latin square, animal within Latin square and period. There was no treatment effect (P>0.05) for the evaluated variables, due to large animal per animal variation. However, by evaluating the mean of milk production as a function of supplementation, there was a trend for curvilinear response, following a Michaelis-Menten relationship of enzymatic systems and was explained by the following equation of Lineweaver-Burk: 1/Milk = 0.0125*(1/Suppl) + 0.0826; r2 = 1.00. The theoretical maximum milk production (1/a) was 12.1 kg/animal/day, and the amount of concentrate to cause half maximum milk production (b/a) was verified with 5.2% of that necessary to reach 95% maximum response. It can be concluded that the marginal increase in milk production reduces with increasing supplementation, in which the adequate level of supplementation is between 1.25 and 2.5 kg of concentrate/cow/dayObjetivou-se avaliar os efeitos da quantidade de suplementos na produção e composição do leite. Foram utilizadas oito vacas mestiças Holandês-Zebu, com 517±40 kg de peso médio, distribuídas estatisticamente na forma de dois quadrados latinos 4 x 4, em quatro períodos de 14 dias. O experimento foi conduzido em pasto de capim-elefante (Pennisetum purpureum, Schum) na estação chuvosa, e os tratamentos incluíram um controle (mistura mineral) e suplementos com 24% de proteína bruta na matéria seca nos níveis de 1,25; 2,5; e 5,0 kg/animal/dia, baseado em fubá de milho, farelo de soja, uréia e mistura mineral. O experimento foi analisado em quadrado latino incluindo efeitos de tratamento, quadrado latino, animal dentro de quadrado latino e período. Não houve efeito de tratamento (P>0,05) para as variáveis analisadas, devido à grande variação de animal para animal. Entretanto, ao avaliar a média da produção de leite em função da suplementação, houve tendência de resposta curvilínea, seguindo o modelo de Michaelis-Menten de sistemas enzimáticos, e foi explicada pela seguinte equação de Lineweaver-Burk: 1/leite = 0,0125*(1/supl) + 0,0826; r2 = 1,00. A produção máxima teórica de leite (1/a) foi de 12,1 kg/animal/dia, e a quantidade de concentrado para causar metade da produção máxima de leite (b/a) foi observada com 5,2% daquela necessária para atingir 95% da resposta máxima. Conclui-se que o aumento marginal na produção de leite reduz com o aumento na suplementação, sendo que o nível adequado de suplementação está entre 1,25 e 2,5 kg de concentrado/vaca/dia

ESTRATÉGIAS NUTRICIONAIS PARA AUMENTAR AS PROPRIEDADES NUTRACÊUTICAS DO LEITE: CONCENTRAÇÕES DE ENTEROLACTONA E ÁCIDO LINOLEICO CONJUGADO

This study aimed to describe nutritional strategies to increase milk nutraceutical properties, including mainly strategies to increase the concentrations of enterolactone (EL) and conjugated linoleic acid (CLA). Enterolactone and CLA are endogenously produced from dietary components and have been identified as nutraceutical compounds with the potential of improving human health through the prevention and treatment of diseases. The concentration of these compounds in milk can be modulated through nutritional strategies which enable to produce milk with greater potential for improving human health. The inclusion of vegetable lignans sources, such as flaxseed meal and the inclusion of sucrose sources in the diet of dairy cows increase the concentration of EL in milk. Feeding sources of polyunsaturated fatty acids, such as vegetable oils, results in increased concentration of CLA in milk. The application of animal nutrition to increase nutraceutical properties of milk is a valuable tool for promoting the association of milk with human health benefits and is of great interest.Objetivou-se descrever estratégias nutricionais para aumentar as propriedades nutracêuticas do leite, incluindo principalmente estratégias para o aumento nas concentrações de enterolactona (EL) e ácido linoleico conjugado (CLA). Os compostos EL e CLA, ambos produzidos endogenamente a partir de componentes da dieta, são compostos bioativos presente no leite e têm sido apontados como compostos nutracêuticos, capazes de melhorar a saúde humana através da prevenção e tratamento de doenças. Estratégias nutricionais aplicadas na alimentação de vacas leiteiras possibilitam o aumento da concentração destes compostos no leite, tornando possível a produção de leite com maior potencial de beneficiamento a saúde humana. A inclusão de fontes de lignanas vegetais, como por exemplo, o farelo de linhaça e a inclusão de fontes de sacarose na dieta de vacas leiteiras possibilitam aumentar a concentração de EL no leite. Da mesma forma, o fornecimento de fontes ricas de ácidos graxos polinsaturados, como por exemplo, os óleos vegetais, possibilita o aumento da concentração de CLA no leite. A temática da nutrição animal voltada para o aumento das propriedades nutracêuticas do leite, apesar de estar iniciando, apresenta grande perspectiva, e é uma ferramenta valiosa para promoção da associação do leite com benefícios a saúde humana. Palavras-chave: nutracêutico; compostos bioativos; lignanas; vacas de leite; benefícios do leite; redução do risco de doenças.   Nutritional strategies to improve nutraceutical proprieties of milk: improvements on milk enterolactone and conjugated linoleic acid   ABSTRACT: This study aimed to describe nutritional strategies to increase milk nutraceutical properties, including mainly strategies to increase the concentrations of enterolactone (EL) and conjugated linoleic acid (CLA). Enterolactone and CLA are endogenously produced from dietary components and have been identified as nutraceutical compounds with the potential of improving human health through the prevention and treatment of diseases. The concentration of these compounds in milk can be modulated through nutritional strategies which enable to produce milk with greater potential for improving human health. The inclusion of vegetable lignans sources, such as flaxseed meal and the inclusion of sucrose sources in the diet of dairy cows increase the concentration of EL in milk. Feeding sources of polyunsaturated fatty acids, such as vegetable oils, results in increased concentration of CLA in milk. The application of animal nutrition to increase nutraceutical properties of milk is a valuable tool for promoting the association of milk with human health benefits and is of great interest. Keywords: nutraceutical proprieties; bioactive compounds; lignans; dairy cows; health benefits of milk; disease risk reduction

Níveis de concentrados para vacas de leite em sistema confinado e sua implicação na composição e produção do leite

Avaliaram-se os efeitos da quantidade de concentrado sobre a produção e composição do leite de vacas mestiças Holandês-Zebu com peso médio de 515 ± 38 kg, entre a 3a e 5a lactações, recebendo cana-de-açúcar acrescida de 0,25% de mistura ureia/sulfato de amônia como volumoso. Oito vacas foram distribuídas em dois quadrados latinos 4x4 e os tratamentos consistiram de um controle onde apenas sal mineral foi fornecido e três níveis de concentrados: 1,25; 2,5; e 5,0 kg animal-1 dia-1 à base de milho, farelo de soja, mistura de ureia/sulfato de amônia 9:1 e sal mineral. O experimento foi analisado em quadrado latino (QL) incluindo efeitos de tratamento, QL, animal/QL e período/QL. Não houve efeito de tratamento para as variáveis analisadas, mas houve tendência de resposta curvilínea na produção de leite, seguindo o relacionamento de Michaelis-Menten, sendo explicada pela seguinte equação de Lineweaver-Burk: 1/leite = 0,0065*(1/supl) + 0,1093; r2 = 0,96. A produção máxima teórica de leite (1/a) foi de 9,1 kg animal-1 dia-1, e a quantidade de concentrado para causar metade da produção máxima de leite (b/a) foi verificada com 5,2% daquela para atingir 95% da resposta máxima. O aumento marginal na produção de leite reduz com a suplementação, sendo diferente do NRC 2001, que considera resposta linear ao suprimento de energia ou de proteína

Eficiência de utilização de concentrado na produção de leite em vacas da raça Gir linhagem leiteira sob confinamento ou pastejo

Avaliaram-se a eficiência de utilização de suplementos na produção de leite de vacas da raça Gir Leiteiro em dois experimentos. O primeiro experimento foi conduzido com 20 vacas em confinamento, distribuídas em delineamento em blocos casualizados, com quatro tratamentos e cinco repetições. Os tratamentos experimentais foram quatro níveis de concentrado (NC) com quatro níveis de proteína bruta (PB, base da MS da dieta): 11,7% de NC e 11,0% de PB; 23,3% de NC e 12,0% de PB; 35,2% de NC e 14,0% de PB; 46,8% de NC e 16,0% de PB. Utilizou-se a silagem de sorgo como volumoso. No segundo experimento, 21 vacas foram avaliadas quanto ao efeito do nível crescente de concentrados, sendo os animais mantidos em pastagem de capim elefante (Pennisetum purpureum). Os tratamentos consistiram de três níveis de concentrado (2,0; 4,0 e 6,0 kg/vaca/ dia) e dois níveis de PB na matéria seca total da dieta (14 e 16%), mais um tratamento testemunha, num esquema fatorial 3 x 2 + 1. Os dados foram aplicados no modelo Lineweaver-Burk, sendo feita a análise de regressão linear da recíproca de reposta de produção em função da recíproca do suprimento de nutrientes. A produção máxima teórica foi de 12,94 e 12,77 kg de leite/vaca/dia e a quantidade de suplemento para atingir metade da produção máxima teórica de leite (K s ) foi de 0,34 e 0,17 kg/vaca/dia, para os animais mantidos em confinamento e pastejo. A eficiência de utilização de concentrado é decrescente e para as condições avaliadas é menor para animais mantidos em pastejo.Two experiments were performed with milking Gyr cows with the objective of evaluating the efficiency of supplements use in milk production. EXP 1 was carried out with 20 cows confined, being distributed in random blocks design, with for treatments and five replicates. The experimental treatments were composed by four diets containing four levels of concentrate (LC) and four levels of crude protein (CP, dietary dry matter basis): 11.7% LC and 11% CP; 23.2% LC and 12% CP; 35.2% LC and 14% CP; and 46.8% LC and 16% CP. Sorghum silage was used as forage. In EXP II, 21 cows were evaluated with increasing levels of concentrate, being the animals maintained in pastures of elephant grass (Pennisetum purpureum). The treatments were based on three levels of concentrate ration (2, 4, and 6 kg/cow/day) and two levels of CP in the total dietary dry matter (12 and 15%), plus an control treatment, in an 3 x 2 + 1 factorial arrangement. The animal response to supplementation was analyzed by Lineweaver-Burk model, using linear regression of the reciprocal of milk production as a function of reciprocal of nutrients supply. The theoretical maximum production was 12.94 and 12.77 kg of milk/cow/day and the amount of supplement to reach half of theoretical maximum production (Ks) was 0.34 and 0.17 kg/cow/day for the animals maintained in confined and pasture. Thus, the efficiency of concentrate utilization decreases and for the evaluated conditions it is lowest for the pasture fed animals