Effects of nutrition on the contents of fat, protein, somatic cells, aromatic compounds, and undesirable substances in sheep milk

Pulina, Giuseppe; Nudda, Anna; Battacone, Gianni; Cannas, Antonello

doi:10.1016/j.anifeedsci.2006.05.023

Cited by 163 publications

(153 citation statements)

References 125 publications

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“…Previous studies have shown increases in milk yield and reductions in milk protein when sheep diets are supplemented with fat or oil (Pulina et al, 2006). These changes can probably be explained by the greater energy content of the lipid-supplemented diets compared with the nonsupplemented ones, and the reduced amino-acid availability in the mammary gland.…”

Section: Resultsmentioning

confidence: 98%

Effects of olive and fish oil Ca soaps in ewe diets on milk fat and muscle and subcutaneous tissue fatty-acid profiles of suckling lambs

Gallardo

Gómez‐Cortés

Mantecón

et al. 2014

animal

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Enhancing healthy fatty acids (FAs) in ewe milk fat and suckling lamb tissues is an important objective in terms of improving the nutritional value of these foods for the consumer. The present study examined the effects of feeding-protected lipid supplements rich in unsaturated FAs on the lipid composition of ewe milk, and subsequently in the muscle and subcutaneous adipose tissues of lambs suckling such milk. Thirty-six pregnant Churra ewes with their new-born lambs were assigned to one of three experimental diets (forage/concentrate ratio 50 : 50), each supplemented with either 3% Ca soap FAs of palm (Control), olive (OLI) or fish (FO) oil. The lambs were nourished exclusively by suckling for the whole experimental period. When the lambs reached 11 kg BW, they were slaughtered and samples were taken from the Longissimus dorsi and subcutaneous fat depots. Although milk production was not affected by lipid supplementation, the FO diet decreased fat content ( P < 0.001), whereas the OLI milk FA profile resembled that of the Control diet. In contrast, although FO drastically diminished the contents of stearic and oleic acids ( P < 0.001), all the saturated even-numbered carbon FAs from 6:0 to 14:0 increased ( P < 0.05). FO also produced the highest levels of c9,t11-18:2 (2.21%) and n-3 FAs, 20:5 n-3 (0.58%), 22:5 n-3 (0.48%) and 22:6 n-3 (0.40%). The high levels of trans-11 18:1 (7.10%) obtained from the FO diet would suggest that Ca soaps only confer partial protection in the rumen. In contrast, the lack of significant differences in trans-10 18:1 levels ( P > 0.05) and other trans-FAs between Control and FO treatments would indicate that FO treatment does not alter rumen biohydrogenation pathways under the assayed conditions. Changes in dam milk FA composition induced differences in the FA profiles of meat and fat depots of lambs, preferentially incorporated polyunsaturated FAs into the muscle rather than storing them in the adipose tissue. In the intramuscular fat of the FO treatment, all the n-3 FAs reached their highest concentrations: 0.97 (18:3 n-3), 2.72 (20:5 n-3), 2.21 (22:5 n-3) and 1.53% (22:6 n-3). In addition, not only did FO intramuscular fat have the most cis-9, trans-11 18:2 (1.66%) and trans-11 18:1 (3.75%), but also the lowest n-6/n-3 ratio (1.80) and saturated FA content were not affected. Therefore, FO exhibited the best FA profile from a nutritional point of view.

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Section: Resultsmentioning

confidence: 98%

Effects of olive and fish oil Ca soaps in ewe diets on milk fat and muscle and subcutaneous tissue fatty-acid profiles of suckling lambs

Gallardo

Gómez‐Cortés

Mantecón

et al. 2014

animal

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“…The pattern of protein concentration showed the well-known concentration effect associated with a reduction in milk yield (Pulina et al, 2006). The initial milk protein concentration was reached at the Re-Fed period.…”

Section: Milk Yield and Compositionmentioning

confidence: 90%

Effects of short-term feed restriction on milk yield and composition, and hormone and metabolite profiles in mid-lactation Sarda dairy sheep with different body condition score

Pulina

Nudda

Battacone

et al. 2012

Italian Journal of Animal Science

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“…Indirect comparisons of changes in milk fat composition to diets of similar composition (Table 4) combined with comparisons of changes in milk fat secretion to rumen protected sources of trans-10, cis-12 CLA ( Figure 5) and the relationship between increases in trans-10 18:1 and changes in milk fat synthesis (Figure 7a) suggest that small ruminants differ from cows with respect to both ruminal lipid metabolism and the regulation of mammary lipogenesis. Ruminal biohydrogenation pathways appear to be more stable and robust to alterations due to diet in small ruminants compared with the cow that may reflect differences between species related to eating behavior, rumination, buffering of rumen pH, rumen digestion kinetics and transit rates (Chilliard et al, 2003;Pulina et al, 2006;Bernard et al, 2009c) resulting in less exposure of the mammary gland to TFA that may inhibit milk fat synthesis. This is supported by a recent experiment demonstrating that supplements of fish oil and soya bean oil (30 and 109 g/day) to goats grazing fresh grass enhanced milk fat content (mean response 8 g/kg) and milk trans-11 18:1 concentrations (mean response 11.9 g/100 g fatty acids) in the absence of large changes (mean response 0.9 g/100 g fatty acids) in milk trans-10 18:1 content (Gagliostro et al, 2009), whereas fish oil and sunflower oil causes MFD in lactating cows fed maize silage based diets and increases in milk fat trans-10 18:1 and trans-9, cis-11 CLA concentrations (Shingfield et al, 2006a).…”

Section: Role Of Ruminal Biohydrogenation On Mammary Lipogenesis In Smentioning

confidence: 99%

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

Shingfield

Bernard

Leroux

et al. 2010

Animal

322

425

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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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Effects of nutrition on the contents of fat, protein, somatic cells, aromatic compounds, and undesirable substances in sheep milk

Cited by 163 publications

References 125 publications

Effects of olive and fish oil Ca soaps in ewe diets on milk fat and muscle and subcutaneous tissue fatty-acid profiles of suckling lambs

Effects of olive and fish oil Ca soaps in ewe diets on milk fat and muscle and subcutaneous tissue fatty-acid profiles of suckling lambs

Effects of short-term feed restriction on milk yield and composition, and hormone and metabolite profiles in mid-lactation Sarda dairy sheep with different body condition score

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

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