Effect of 2-hydroxy-4-(methylthio)butanoate (HMTBa) on risk of biohydrogenation-induced milk fat depression

Abstract

Diet-induced milk fat depression (MFD) is a multifactorial condition resulting from the interaction of numerous risk factors, including diet fermentability and unsaturated fatty acids concentration, feed additives, and individual cow effects. 2-Hydroxy-4-(methylthio)butanoate (HMTBa) is a methionine analog that has been observed to increase milk fat in some cases, and interactions with MFD risk factors may exist. The objective was to evaluate the effect of HMTBa supplementation on milk fat synthesis in cows with different levels of milk production and fed diets with increasing risk of biohydrogenation-induced MFD. Sixteen high-producing cows (44.1 ± 4.5 kg of milk/d; mean ± SD) and 14 low-producing (31.4 ± 4.3 kg of milk/d) were used in a randomized block design. Treatments were unsupplemented control and HMTBa fed at 0.1% of diet dry matter (25 g/d at 25 kg of dry matter intake). The experiment was 70 d and included a 14-d covariate period followed by 3 phases whereby diets were fed with increasing risk of MFD to determine the interaction of treatment and diet-induced MFD. During the low-risk phase, the base diet was balanced to 33.5% neutral detergent fiber (NDF) and had no exogenous oil (28 d); during the moderate-risk phase, the diet was balanced to 31% NDF and contained 0.75% soybean oil (14 d); and, during the high-risk phase, the diet was balanced to 28.5% NDF and contained 1.5% soybean oil (14 d). An interaction of treatment, production-level, and dietary phase was observed. Low producing cows neither experienced substantial biohydrogenation-induced MFD nor a response in milk fat to HMTBa supplementation. In high-producing cows, HMTBa maintained higher milk fat concentration during the moderate- (2.94 vs. 3.49%) and high-risk (2.38 vs. 3.11%) phases. High-producing cows receiving HMTBa also had greater milk fat yield (0.94 vs. 1.16 kg/d) and lower trans-10 C18:1 (6.11 vs. 1.50) during the high-risk phase. In conclusion, HMTBa increased milk fat in situations with a high risk of biohydrogenation-induced MFD by decreasing absorption of alternate biohydrogenation intermediates.

266 Evaluation of peri-partum supplementation of methionine hydroxy analog on cow-calf performance.

“…It has been demonstrated that at a maximum, 50% of HMTBa escapes ruminal degradation (Koenig et al, 1999) and becomes available for intestinal absorption; however, this value has been considerably lower in other studies (Noftsger et al, 2005). With some studies focusing on the effect HMTBa has on alleviating diet-induced milk fat depression (MFD) and altering ruminal biohydrogenation (Baldin et al, 2018), it could be argued that the response in percent milk fat in the current study was due more to HMTBa utilized in the rumen rather than the HMTBa that reached the small intestine for absorption. If that is indeed the case, HMTBa still represents a differential niche compared to free methionine (Met) because of its ability to be absorbed across the rumen wall via passive diffusion and paracellular transfer (McCollum et al, 2000).…”

“…Much of the dairy literature that has denoted an improvement in percent milk fat have revolved around studies simulating diet-induced milk fat depression (MFD) where HMTBa modulated rumen biohydrogenation. Though the cows in the current study were likely not high enough producing, or the diet too severe in carbohydrate fermentability or polyunsaturated fatty acid (PUFA) levels to induce MFD (Baldin et al, 2018), it is possible that an alteration in biohydrogenation in the rumen was the cause behind the increase in milk fat.…”

“…These include a stimulating effect on de novo synthesis of short-and medium-chain fatty acids in the mammary gland (Pisulewski et al, 1996) and Met's role as a methyl donor in the synthesis of choline (Sharma and Erdman, 1988) or increasing triglycerides and lipoproteins in the blood (Huber et al, 1984), both of which are imperative in the synthesis of milk fat. Due to 50 to 60% of HMTBa being utilized in the rumen, multiple studies (Baldin et al, 2015(Baldin et al, , 2018 biohydrogenation is altered to produce unique fatty acid intermediates such as trans-10, cis-12 CLA, which has been shown to be a potent inhibitor on the mammary gland's ability to synthesize milk fat (Bauman and Griinari, 2003;Harvatine, 2016).…”

“…A meta-analysis conducted by Zanton et al (2014) discovered an increase in percent milk fat due to HMTBa supplementation, but production responses to HMTBa reported in the literature varied significantly across studies. Multiple studies have indicated no effect on milk production or milk composition Lapierre et al, 2011;Lee et al, 2015), while others saw boosts in percent milk fat (Lundquist et al, 1985;Hansen et al, 1991;Baldin et al, 2018), or milk yield (Piepenbrink et al, 2004;Wang et al, 2010). The conflicting results across studies can be attributed to a variety of factors including but not limited to the level of inclusion rate of HMTBa, day of sample relative to parturition, success/failure in truly meeting daily dietary nutrient requirements, and the variation in metabolism and milk production between dairy and beef cows.…”

Night-restricted feeding of dairy cows modifies daily rhythms of feed intake, milk synthesis and plasma metabolites compared with day-restricted feeding

“…One subsample was stored at 4°C with a preservative (Bronolab-WII; Advanced Instruments, Inc.) prior to analysis of fat and protein concentration by Fourier transform infrared spectroscopy (Fossomatic 4000 Milko-Scan and 400 Fossomatic, Foss Electric; Dairy One DHIA). A second subsample was stored without preservative at 4°C and centrifuged at 2300 g within 12 h. The resulting fat cakes were stored at −20°C and analysed for concentrations of individual fatty acids (FA) according to Baldin et al (14) .…”