ABSTRACT
The fatty acid (FA) and phospholipid composition of dietary lecithin may influence FA digestibility and milk production in cattle. Eight multiparous Holstein cows (99.4 ± 9.2 d in milk [DIM]; 48.9 ± 3.8 kg milk/d) were enrolled in a 3 × 3 incomplete Latin square design with 3 treatments provided as continuous abomasal infusates spanning 14-d experimental periods: water (CON), soybean phospholipids (SOY; 74.5 g of deoiled soy lecithin), or sunflower phospholipids (SUN; 133.5 g of hydrolyzed sunflower lecithin). Cows were fed the same diet, which contained (% dry matter) 27.0% neutral detergent fiber (NDF), 15.6% crude protein (CP), 26.2% starch, and 5.87% FA. Treatments did not modify body weight, milk fat, protein, or lactose contents, or the efficiency of producing energy-corrected milk. Cows infused with SUN had greater milk yields than those receiving SOY or CON treatments. Cows infused with SUN had higher total solids, protein, and lactose yields than cows receiving the SOY or CON treatments. Sunflower phospholipids enhanced feed efficiency (milk yield/dry matter intake) relative to SOY or CON. Treatment did not affect intakes or apparent total-tract digestibilities for NDF, CP, starch, or 16-carbon (16C) FA. Cows receiving SUN had greater total FA and 18-carbon (18C) FA intakes than SOY or CON, but treatments did not impact their digestibility. Milk FA composition was modified by treatment. Cows receiving SUN had a greater concentration of polyunsaturated FA and lower concentrations of saturated FA and monounsaturated FA in milk relative to SOY or CON. In conclusion, the abomasal infusion of SUN improved milk production and milk FA composition, indicating potential benefits for dairy cow nutrition and milk quality.
ABSTRACT
Finite natural resources, rising human population, and climate change pose challenges to traditional crop production. Hydroponically grown fodder (i.e., sprouted grains) can be an alternative feed source for dairy cows; however, only sprouted barley has been investigated in low-producing cows. We aimed to evaluate the impact of replacing conventional concentrates with sprouted barley or wheat, grown using hydroponics, on milk production, nutrient digestibility, and milk fatty acid profile in high-producing cows. Twenty-four multiparous Holstein cows [3.25 ± 1.33 lactations; 102 ± 23 d in milk (DIM); 49 ± 4 kg/d of milk] were used in a replicated 3 × 3 Latin square design with 21-d experimental periods. Following a 2-wk covariate period, cows were fed 1 of 3 experimental diets: a total mixed ration (1) without sprouted grains (Control), or with (2) 10% sprouted barley (Barley) or (3) 10% sprouted wheat (Wheat) on a dry matter (DM) basis. Experimental diets were formulated to be isoenergetic and isonitrogenous with sprouted grains that replaced ground corn, soybean meal, canola meal, and dextrose. Sprouted grains were grown using a semi-automatic hydroponic system and harvested after 6 d of growth. Data and sample collection occurred during the last 3 d of the covariate and experimental periods. Wide ranges were observed for the DM percent of sprouted grains (12.1 to 22.9% and 13.3 to 25.7% for barley and wheat, respectively) and the ratio of sprouted fodder to seed (0.67 to 1.07 for both barley and wheat). Feeding sprouted grains did not modify yields of milk or energy-corrected milk (ECM); however, dry matter intakes (DMI) were lower for Barley, relative to Control. Feed efficiencies were greater for Barley than for Control (1.49 ± 0.03 vs. 1.43 ± 0.03 for milk yield/DMI; 1.85 ± 0.03 vs. 1.73 ± 0.04 for ECM/DMI). Yields and concentrations of milk components (i.e., fat, true protein, and lactose) were not impacted by treatment. Milk urea-N concentrations were greater for Wheat, relative to Control or Barley. Body weight (BW; 752 ± 3 vs. 742 ± 3 kg) and BW gain (6.53 ± 2.99 vs. -9.33 ± 2.91 kg/21 d) were higher for Wheat than for Control. Apparent total-tract digestibility of organic matter was greater for Wheat, relative to Barley. Digestibilities of neutral detergent fiber and starch were higher for Wheat and Control, relative to Barley, and crude protein digestibility was greater for Wheat, relative to Barley and Control. Rumination and physical activity were not impacted by treatment. In summary, replacing traditional concentrates with sprouted grains grown using hydroponics improved milk production efficiency (barley sprouts) or enhanced body weight gain (wheat sprouts). A life cycle assessment needs to be conducted to determine the net impact of this feeding strategy for the dairy industry.
ABSTRACT
The fungal isolate myriocin inhibits serine palmitoyltransferase and de novo ceramide synthesis in rodents; however, the effects of myriocin on ceramide concentrations and metabolism have not been previously investigated in ruminants. In our study, 12 non-lactating crossbred ewes received an intravenous bolus of myriocin (0, 0.1, 0.3, or 1.0 mg/kg/body weight [BW]; CON, LOW, MOD, or HIGH) every 48 h for 17 d. Ewes consumed a high-energy diet from day 1 to 14 and were nutrient-restricted (straw only) from day 15 to 17. Blood was collected preprandial and at 1, 6, and 12 h relative to bolus and nutrient restriction. Tissues were collected following euthanasia on day 17. Plasma was analyzed for free fatty acids (FFAs), glucose, and insulin. Plasma and tissue ceramides were quantified using mass spectrometry. HIGH selectively decreased metabolizable energy intake, BW, and plasma insulin, and increased plasma FFA (Dose, P < 0.05). Myriocin linearly decreased plasma very-long-chain (VLC) ceramide and dihydroceramide (DHCer) by day 13 (Linear, P < 0.05). During nutrient restriction, fold-change in FFA was lower with increasing dose (P < 0.05). Nutrient restriction increased plasma C16:0-Cer, an effect suppressed by MOD and HIGH (Dose × Time, P < 0.05). Myriocin linearly decreased most ceramide and DHCer species in the liver and omental and mesenteric adipose, VLC ceramide and DHCer in the pancreas, and C18:0-Cer in skeletal muscle and subcutaneous adipose tissue (Linear, P ≤ 0.05). We conclude that the intravenous delivery of 0.3 mg of myriocin/kg of BW/48 h decreases circulating and tissue ceramide without modifying energy intake in ruminants.
