Feeding different dietary protein to energy ratios to Holstein heifers: effects on growth performance, blood metabolites and rumen fermentation parameters

Abstract

Eighteen Chinese Holstein heifers average age 230 ± 14 days were allocated to 1 of 3 dietary crude protein (CP) to metabolizable energy (ME) ratios to examine the effects on growth performance, blood metabolites and rumen fermentation parameters with 90-days experiment. Three different dietary CP:ME ratios were targeted based on the formulation of dietary CP contents of 10.85%, 12.78% and 14.63% on dry matter (DM) basis with similar ME contents (10.42 MJ/kg DM), which were categorized as low, medium and high dietary CP:ME ratios. The actual CP:ME ratios obtained in this study significantly increased from low to high CP:ME ratio groups with a value of 10.59, 11.83 and 13.38 g/MJ respectively. Elevated CP:ME ratios significantly increased CP intake (kg/day) and feed efficiency (FE) which was defined as dry matter intake as a proportion of average daily gain (ADG), whereas little difference was observed in body weight (kg), ADG (kg/day), DM intake (kg/day) and ME intake (MJ/day) among the three different CP:ME ratio groups. Increasing dietary CP to ME ratios significantly increased CP digestibility, whereas digestibility of DM and gross energy remained constant in the current experiment. Blood urea nitrogen and insulin-like growth factor-1 linearly increased with increasing dietary CP:ME ratios. There was significantly dietary treatment effect on rumen fermentation parameters including acetate, propionate, butyrate and total volatile fatty acids. Therefore, this study indicated that increasing dietary CP levels with similar energy content contributed to increased protein intake and its digestibility, as well as FE. Holstein heifers between 200 and 341 kg subjected to 13.38 dietary CP:ME ratio showed improved feed efficiency, nutrient digestibility, some blood metabolites and rumen fermentation characteristics for 0.90 kg/day rate of gain.

Effect of Dietary Concentrate to Roughage Ratio on Nutrient Digestibility, Rumen Fermentation, Growth Performance and Serum Acute Phase Protein in Growing Buffalo Calves

“…This result support the previous report of Serment et al (2011). Abonyi et al (2013), Chen et al (2015) and Dong et al (2017) who revealed that the high concentrate diet probably improved energy balance, protein synthesis and humoral immunity of the animal. Blood urea nitrogen (BUN) concentration was used as indicator of nitrogen utilization efficiency by ruminants (Lewis, 1957).…”

Partial phenotype conversion and differential trait response to conditions of husbandry in mice

“…In rats, direct comparison of a high versus low protein diet during pregnancy and lactation revealed higher growth rates in the offspring in a sex-specific manner (Thone-Reineke et al 2006 ). The protein-to-energy ratio also was demonstrated in non-rodent animals as an important determinant of weight gain (Garling and Wilson 1976 ; Dong et al 2017 ). An excess of protein intake in mice by means of a 40% protein diet, impaired postnatal growth (Kucia et al 2011 ), supporting a major effect of macronutrient composition also in mice.…”

Temporal changes in liver tissue metabolome of lambs fed low‐quality roughage

“…Moreover, the CPI/MEI was the lowest in P3, suggesting an imbalance of dietary CP/ ME. It is suggested that nitrogen utilization in ruminants is influenced by dietary ME and CP content, as well as their proportion (Dong et al 2017), while the liver is the important organ in nitrogen utilization. Thus, several amino acids and amino acid metabolism-related metabolites were observed to decrease in liver in P3.…”