Composição em ácidos graxos do leite de vacas alimentadas com glicerina de baixa pureza

Filho

et al. 2019

SCA

Sugarcane is a strategic roughage source for milk production in the tropics, and its supplementation with plant oils offers great potential for obtaining milk enriched with beneficial fatty acids, such as oleic (cis-9 C18:1), vaccenic (trans-11 C18:1), and rumenic (cis-9, trans-11 CLA) acids. The aim of this study was to evaluate the milk fatty acid composition of cows fed 60% chopped sugarcane-based diets containing citrus pulp and 0.0% (control), 1.5%, 3.0% and 4.5% sunflower oil on a dry matter basis. Twelve multiparous Holstein x Gyr dairy cows with an average milk production of 17±5 kg day-1 and 96±25 days in milk were allocated in a triplicate 4 x 4 Latin square design. There was no effect of dietary treatment on milk production, but sunflower oil supplementation linearly reduced the milk fat content and yield. The milk fat contents of lauric (C12:0), myristic (C14:0), and palmitic (C16:0) fatty acids were linearly reduced with increasing sunflower oil levels. There was a quadratic effect on the milk fat oleic, vaccenic, and rumenic acid contents, while the concentrations of elaidic acid (trans-9 C18:1), trans-10 C18:1 and trans-10, cis-12 CLA linearly increased in response to sunflower oil inclusion. Diet supplementation with sunflower oil linearly reduced both the atherogenicity and thrombogenicity indices and linearly increased the ratio between hypo- and hypercholesterolemic fatty acids in milk fat. The inclusion of up to 4.5% sunflower oil in 60% chopped sugarcane-based diets improved the nutritional quality of milk fat from Holstein x Gyr dairy cows as a result of the increased content of oleic, rumenic and vaccenic acids, which are beneficial to human health, and the concomitant reduction of hypercholesterolemic lauric, myristic and palmitic acids. However, there was an increase in the milk content of trans-10 C18:1 and elaidic acid, which are associated with deleterious effects on cardiovascular health.

Section: Apparentmentioning

confidence: 83%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Milk fatty acid composition of Holstein x Gyr dairy cows fed sugarcane-based diets containing citrus pulp supplemented with sunflower oil

Souza

Filho

et al. 2019

SCA

“…SO increased the omasal digesta vaccenic acid content (Table 7) as shown by the regressions (P<0.0001) between the omasal digesta content of vaccenic acid (y; g 100 g -1 FA) versus intakes (x; g cow -1 day -1 ) of oleic (ŷ = 0.05008*x; r 2 adj = 0.80), linoleic (ŷ = 0.02034*x; r 2 adj = 0.79) and α-linolenic acids (ŷ = 0.41786*x; r 2 adj = 0.77). The milk fat rumenic acid contents obtained from 30-45 g kg -1 SO diets (Table 9) were higher compared to the range of 0.56-2.05 g 100 g -1 FA reported for cows fed diets based on 400-630 g kg -1 sugarcane with lipid supplementation (Meneses et al, 2015;Rodrigues et al, 2019). In the productive performance trial, Souza et al (2019) obtained higher milk fat rumenic acid contents in all SO diets, i.e., 1.46, 2.41, and 2.77 g 100 g -1 FA in the diets with 15, 30, and 45 g kg -1 SO, respectively.…”

Section: Discussionmentioning

confidence: 59%

Ruminal parameters and fatty acid composition of omasal digesta and milk in cows fed sugarcane-based diets supplemented with sunflower oil

Souza

Filho

et al. 2020

Semina: Ciênc. Agrár.

This study evaluates the intake and digestion of nutrients, parameters of rumen fermentation and degradation, omasal digesta and milk fatty acid composition, productive performance, and the concentration of serum metabolites in cows fed 600 g kg-1 sugarcane-based diets containing 0 (control), 15, 30, and 45 g kg-1 sunflower oil (SO) on a dry matter (DM) basis. Four rumen-cannulated Holstein x Gyr cows yielding 15±5 kg day-1 with 110±10 days in milk were allocated in a 4 x 4 Latin square design. Data were analyzed using mixed models, and significant differences were declared at P < 0.05. There was no effect of SO on the intake and apparent digestibility of DM, crude protein, neutral detergent fiber (NDF) and nonfibrous carbohydrates, but there was a linear increase in the intake and digestibility of ether extract. Dietary SO levels did not alter the ruminal degradability parameters for DM and NDF, rumen pH and contents of ammonia N, acetate, propionate and volatile fatty acids. Milk fat content and yield were linearly decreased, whereas a linear increase in milk protein content was observed in response to increasing levels of SO, but with no effect on milk yield. Linear reductions in palmitic and ?-linolenic acid contents, a linear increase in trans-10 C18:1 and elaidic acids, and a quadratic effect on vaccenic and rumenic acids were observed in omasal digesta of cows fed increasing levels of SO. Overall, up to 45 g kg-1 SO can be included on DM of chopped sugarcane-based diets without reducing consumption, apparent digestibility and rumen degradability of DM and fiber. Supplementing chopped sugarcane-based diets with 30 to 45 g kg-1 SO (DM basis) promotes milk fat depression due to the inhibition of mammary lipogenesis by specific rumen-derived fatty acid intermediates of the biohydrogenation of unsaturated C18 fatty acids. The inclusion of 15 to 45 g kg-1 SO in chopped sugarcane-based diets improves the nutritional quality of milk fat, with increases in the levels of oleic, vaccenic and rumenic acids, beneficial to human health, and a reduction in the levels of the hypercholesterolemic lauric, myristic and palmitic acids.

“…Low contents of rumenic acid have been reported in milk fat from cows fed diets based on fresh sugarcane (Meneses et al, 2015;Pimentel et al, 2016;Souza et al, 2019) or sugarcane silage (Martins et al, 2016) without lipid supplementation. However, a marked increase (~388-395%) in milk fat rumenic acid content was found when cows were fed fresh sugarcane-based diets supplemented with ingredients rich in oleic and linoleic (cis-9, cis-12 C18:2) acids (Meneses et al, 2015;Souza et al, 2019).…”

Section: Introductionmentioning

confidence: 99%

Ruminal fermentation and degradation, kinetic flow of digesta and milk fatty acid composition of cows fed sugarcane silage-based diets supplemented with whole cottonseed

Costa

Rebouças

et al. 2020

SCA

The aim of this study was to evaluate the ruminal fermentation and degradation parameters, the kinetic flow of digesta in the gastrointestinal tract, and the milk fatty acid (FA) profile in Holstein x Gyr cows fed 59% sugarcane silage-based diets with 0% (control), 5%, 10% and 15% whole cottonseed (WCS) on a dry matter (DM) basis. Four rumen-cannulated cows with an average milk yield of 14.4±3.3 kg day-1 and 85±25 days in milk were allocated in a 4 x 4 Latin square design. There was no effect of dietary WCS levels on the intake of organic matter (OM), crude protein (CP), neutral detergent fiber (NDF) and nonfibrous carbohydrates, but there was a linear increase in the intake of ether extract (EE). There was no treatment effect on the apparent digestibility of DM, OM, CP, EE and NDF or on the ruminal degradability parameters for DM and NDF of sugarcane silage. Also, no treatment effects were observed on rumen pH, ruminal and postruminal particulate passage rates or on the rate of passage of the fluids in the rumen. WCS promoted linear reductions in the milk fat contents of lauric, myristic and palmitic acids and linear increases in the milk fat contents of stearic, oleic, trans-10 C18:1 and elaidic acids. The milk fat contents of vaccenic, rumenic, linoleic and ?-linolenic acids were unaffected by WCS supplementation. The inclusion of up to 15% WCS in sugarcane silage-based diets did not alter the digestibility of nutrients, the rumen degradability of the fiber, or the kinetic flow of digesta in the gastrointestinal tract of Holstein x Gyr cows but improved the nutritional quality of milk fat through an increase in the content of oleic acid, which is beneficial to human health, and decreased levels of hypercholesterolemic lauric, myristic and palmitic acids.