Effects of Rumen-Protected Niacin on Dry Matter Intake, Milk Production, Apparent Total Tract Digestibility, and Faecal Bacterial Community in Multiparous Holstein Dairy Cow during the Postpartum Period

Abstract

Extensive studies about rumen-protected niacin (RPN) supplementation on dairy cows in early-lactation have been done, but the effects of RPN on changes in dry matter intake (DMI), milk production, feed digestibility, and fecal bacterial community were conflicting. The aim of this study was to investigate them affected by RPN in postpartum cows. Multiparous Holstein dairy cows (n = 12, parity = 3.5 ± 0.5, body weights = 740 ± 28 kg) were divided into two groups supplemented with either 0 (CON) or 20 g/d RPN (RPN). Our results showed that RPN supplementation increased DMI and milk production of cows during the first three weeks after calving (p < 0.05). The concentrations of neuropeptide Y and orexin A were significantly higher in RPN group than that in the CON group during postpartum period (p < 0.05). The apparent total-tract digestibility of nutrients was similar between the CON and RPN groups at 2 weeks after calving (p > 0.05). The 16S rRNA gene sequencing analysis showed that RPN had no impact on the alpha and beta diversity, although 4 genera were changed in cow feces at 14 days after calving. Overall, 20 g/d RPN added to the diet could improve DMI and milk yield up to two weeks after calving with little influence on feed digestibility.

Performance of Lactating Cows Fed Rations Supplemented with Chromium Methionine, Non-protected Niacin and Yeast

“…Feed intake was similar to the findings of Keshri et al [37], Luo et al [32] and Ovinge et al [29]. On the contrary, giving these feed supplements causes changes in the DMI of dairy ruminant [11,34,41].…”

“…On the other hand, niacin supplementation had the ability as a coenzyme to enhance MY, milk composition and FCR by promoting DMI, ruminal microflora growth and activity, microbial protein, feed degradation in the rumen, and preventing disorders like metabolic fatty liver and ketosis [46]. Increased milk yield and FCR by adding niacin supplements are in line with those findings of and Gaowa et al [34], Luo et al [32]. Also, according to Dufva et al [47], supplementation of niacin increased the protein and fat content of dairy cattle milk by increasing microbial protein and enhancing fibre degradation which improved acetate production.…”

“…Similarly, Luo et al [32] observed that higher niacin levels in high-concentrate rations of finishing male cattle enhanced nutrient digestibility. However, niacin supplementation to ruminant rations had no effect or a negative effect on nutrient digestibility [33,34]. On the other hand, Cr-Met is a vital element that supports rumen microflora growth and reproduction and rumen fermentation processes, which enhance nutrient digestibility [35].…”

Niacin Status Indicators and Their Relationship with Metabolic Parameters in Dairy Cows during Early Lactation

“…It is known that the biodegradability of niacin in the rumen is very high and that it takes 6–12 g of niacin to reach the duodenum to provide a biological effect on various blood parameters, such as a decrease in NEFA or BHB or an increase in glucose concentration in early lactation [ 26 ]. Therefore, rumen-protected niacin was made, which showed its effects on all aspects of metabolism, dry matter intake and milk production [ 27 ]. Excess niacin is thought to be rapidly converted to NAD which goes to the liver or adipocytes, and a disorder of its metabolism leads to various health disorders, such as fatty liver, low grade inflammation or insulin resistance [ 28 ].…”