Feed and Animal Factors Influencing Milk Fat Composition

Palmquist, D.L.; Beaulieu, A. D.; Barbano, D.M.

doi:10.3168/jds.s0022-0302(93)77508-6

Cited by 741 publications

(622 citation statements)

References 63 publications

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“…Fat is an important component contributing to the processing attributes and organoleptic properties of milk and dairy products from ruminants (Palmquist et al, 1993;Chilliard and Ferlay, 2004). During recent decades, increasing emphasis has been placed on the contribution of ruminantderived foods on the development or prevention of chronic human diseases including cancer, cardiovascular disease and insulin resistance.…”

Section: Introductionmentioning

confidence: 99%

Role of trans fatty acids in the nutritional regulation of mammary lipogenesis in ruminants

Shingfield

Bernard

Leroux

et al. 2010

Animal

336

427

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Fat is an important constituent contributing to the organoleptic, processing and physical properties of ruminant milk. Understanding the regulation of milk fat synthesis is central to the development of nutritional strategies to enhance the nutritional value of milk, decrease milk energy secretion and improve the energy balance of lactating ruminants. Nutrition is the major environmental factor regulating the concentration and composition of fat in ruminant milk. Feeding low-fibre/high-starch diets and/or lipid supplements rich in polyunsaturated fatty acids induce milk fat depression (MFD) in the bovine, typically increase milk fat secretion in the caprine, whereas limited data in sheep suggest that the responses are more similar to the goat than the cow. Following the observation that reductions in milk fat synthesis during diet-induced MFD are associated with increases in the concentration of specific trans fatty acids in milk, the biohydrogenation theory of MFD was proposed, which attributes the causal mechanism to altered ruminal lipid metabolism leading to increased formation of specific biohydrogenation intermediates that exert anti-lipogenic effects. Trans-10, cis-12 conjugated linoleic acid (CLA) is the only biohydrogenation intermediate to have been infused at the abomasum over a range of experimental doses (1.25 to 14.0 g/day) and shown unequivocally to inhibit milk fat synthesis in ruminants. However, increases in ruminal trans-10, cis-12 CLA formation do not explain entirely diet-induced MFD, suggesting that other biohydrogenation intermediates and/or other mechanisms may also be involved. Experiments involving abomasal infusions (g/day) in lactating cows have provided evidence that cis-10, trans-12 CLA (1.2), trans-9, cis-11 CLA (5.0) and trans-10 18:1 (92.1) may also exert anti-lipogenic effects. Use of molecular-based approaches have demonstrated that mammary abundance of transcripts encoding for key lipogenic genes are reduced during MFD in the bovine, changes that are accompanied by decrease in sterol response element binding protein 1 (SREBP1) and alterations in the expression of genes related to the SREBP1 pathway. Recent studies indicate that transcription of one or more adipogenic genes is increased in subcutaneous adipose tissue in cows during acute or chronic MFD. Feeding diets of similar composition do not induce MFD or substantially alter mammary lipogenic gene expression in the goat. The available data suggests that variation in mammary fatty acid secretion and lipogenic responses to changes in diet composition between ruminants reflect inherent interspecies differences in ruminal lipid metabolism and mammary specific regulation of cellular processes and key lipogenic enzymes involved in the synthesis of milk fat triacylglycerides.Keywords: milk fat, trans fatty acids, gene expression, lipogenesis, ruminants ImplicationsUnderstanding the regulation of milk fat synthesis is central to the development of nutritional strategies to enhance the nutritional value of milk, decrease milk-energ...

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Section: Introductionmentioning

confidence: 99%

Role of trans fatty acids in the nutritional regulation of mammary lipogenesis in ruminants

Shingfield

Bernard

Leroux

et al. 2010

Animal

336

427

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“…Davis and Brown (1970) categorized two types of diets that induce MFD: (1) those that contained high levels of fermentable carbohydrate and low levels of fiber and (2) those that contained high concentrations of unsaturated oils. The extent of MFD with such diets is modified by many factors including associative dietary effects, feed management practices and animal physiological state (see reviews by Sutton, 1989;Grummer, 1991;Palmquist et al, 1993;Chilliard et al, 2000;Lock et al, 2006a). Researchers quickly realized that many diets that caused MFD also resulted in alterations in ruminal environment and fermentation, most notably a decrease in pH and a decrease in the acetate to propionate molar ratio ).…”

Section: Introductionmentioning

confidence: 99%

Recent advances in the regulation of milk fat synthesis

Harvatine

Boisclair

Bauman

2009

Animal

268

272

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In addition to its economic value, milk fat is responsible for many of milk's characteristics and can be markedly affected by diet. Diet-induced milk fat depression (MFD) was first described over a century ago and remains a common problem observed under both intensive and extensive management. The biohydrogenation theory established that MFD is caused by an inhibition of mammary synthesis of milk fat by specific fatty acids (FA) produced as intermediates in ruminal biohydrogenation. During MFD, lipogenic capacity and transcription of key lipid synthesis genes in the mammary gland are down-regulated in a coordinated manner. Our investigations have established that expressions of sterol response element-binding protein 1 (SREBP1) and SREBP-activation proteins are down-regulated during MFD. Importantly, key lipogenic enzymes are transcriptionally regulated via SREBP1. Collectively, these results provide strong evidence for SREBP1 as a central signaling pathway in the regulation of mammary FA synthesis. Spot 14 is also down-regulated during MFD, consistent with a lipogenic role for this novel nuclear protein. In addition, SREBP1c and Spot 14 knock-out mice exhibit reduced milk fat similar to the magnitude and pattern of MFD in the cow. Application of molecular biology approaches has provided the latest chapter in the regulation of milk fat synthesis and is reviewed along with a brief background in nutritional regulation of milk fat synthesis in ruminants.

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“…Foram estudados os efeitos de dois níveis de extrato etéreo, à base de óleo de arroz: T3: nível de 3% na MS (matéria seca) e T5: nível de 5% na MS. As dietas foram formuladas com base nas necessidades fisiológicas de cabras durante a fase inicial de lactação com produção média de 2,5 litros de leite em 24 horas de secreção e percentual de gordura no leite de 3,5, segundo as recomendações do NRC (National..., 1981 A redução da proporção dos ácidos graxos de cadeias curta e média pode ser decorrente da diminuição de precursores da síntese de novo, acetato e β-hidroxibutirato, resultantes da fermentação ruminal, ou da direta inibição do complexo enzimático envolvido na síntese de novo pela ação dos ácidos graxos de cadeia longa dos óleos vegetais (Palmquist et al, 1993). Para a justificativa dos resultados deste experimento, a segunda opção é a mais possível, uma vez que os níveis de percentuais de gordura não foram influenciados pelo tratamento, sugerindo não ter havido dano à produção do acetato em nível ruminal, pois, quando a capacidade dos microrganismos em saturar os ácidos graxos for ultrapassada, os ácidos graxos insaturados Decréscimo na concentração dos ácidos graxos de cadeia curta, principalmente o mirístico, torna-se positivo do ponto de vista da saúde humana, uma vez que excessos nas concentrações desses ácidos na alimentação podem proporcionar sérios problemas à saúde (Fuentes, 1998 Segundo Gulati et al (1997), a quantidade de ácidos graxos transferidos da dieta para a gordura do leite está diretamente relacionada ao nível de proteção implementado à fonte suplementar de óleo e ao tipo de suplemento empregado.…”

Section: Methodsunclassified

Perfil de ácidos graxos do leite de cabras leiteiras alimentadas com dieta contendo dois níveis de óleo de arroz

Vilanova

Osório

Schmidt

et al. 2012

Arq. Bras. Med. Vet. Zootec.

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Foram testados os efeitos de dois níveis de extrato etéreo à base de óleo de arroz no concentrado em 30 cabras Saanen durante a fase inicial de lactação. A alimentação baseou-se na relação 60% de volumoso (feno de alfafa) e 40% de concentrado comercial com dois níveis de extrato etéreo (3% e 5%). As variáveis estudadas foram a quantificação e qualificação do perfil de ácidos graxos do leite total e frente ao tempo de lactação. O acréscimo de óleo de arroz na dieta diminuiu (P<0,05) a concentração de ácidos graxos saturados e aumentou (P<0,05) a concentração de ácidos graxos poli-insaturados no leite caprino. O ácido linoleico conjugado (ALC) também é afetado positivamente pelo acréscimo de óleo de arroz na dieta. A inclusão de óleo de arroz nos níveis de 3% e 5% da matéria seca, na dieta de cabras leiteiras da raça Saanen, influencia o perfil de ácidos graxos do leite, com ênfase no ALC, até a 11ª semana de lactação.

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Feed and Animal Factors Influencing Milk Fat Composition

Cited by 741 publications

References 63 publications

Role of trans fatty acids in the nutritional regulation of mammary lipogenesis in ruminants

Role of trans fatty acids in the nutritional regulation of mammary lipogenesis in ruminants

Recent advances in the regulation of milk fat synthesis

Perfil de ácidos graxos do leite de cabras leiteiras alimentadas com dieta contendo dois níveis de óleo de arroz

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