Energy metabolism by splanchnic tissues of mature sheep fed varying levels of lucerne hay cubes

Abstract

The objective of this study was to determine the pattern of energy metabolites net flux across the portal-drained viscera (PDV) and total splanchnic tissues (TSP) in mature sheep fed varying levels of lucerne hay cubes. Four Suffolk mature sheep (61.4 6 3.6 kg BW) surgically fitted with multi-catheters were fed four levels of dry matter intake (DMI) of lucerne hay cubes ranging from 0.4-to 1.6-fold the metabolizable energy (ME) requirements for maintenance. Six sets of blood samples were simultaneously collected from arterial and venous catheters at 30-min intervals. With increasing DMI, apparent total tract digestibility increased linearly and quadratically for dry matter (P , 0.05), quadratically (P , 0.05) with a linear tendency (P , 0.1) for organic matter and tended to increase quadratically (P , 0.1) for NDF. PDV release of volatile fatty acids (VFA) and b-hydroxybutyric acid was relatively low at 0.4 M and then linearly increased (P , 0.05) with increasing DMI. Net PDV flux of non-esterified fatty acids showed curvilinear decrease from 0.4 to 1.2 M and then increased at 1.6 M. The respective proportions of each VFA appearing in the portal blood differed (P , 0.05) with DMI and this difference was more obvious from 0.4 to 0.8 M than from 0.8 to 1.6 M. Heat production, as a percentage of ME intake (MEI), decreased linearly (P , 0.05) with increasing DMI accounting for 37%, 21%, 16% and 13% for PDV and 62%, 49%, 33% and 27% for TSP at 0.4, 0.8, 1.2 and 1.6 M, respectively. As a proportion of MEI, total energy recovery including heat production, decreased linearly with increasing DMI (P , 0.05) accounting for 113%, 83%, 62% and 57% for PDV and 140%, 129%, 86% and 83% for TSP at 0.4, 0.8, 1.2 and 1.6 M, respectively. Regression analysis revealed a linear response between MEI (MJ/day per kg BW) and total energy release (MJ/day per kg BW) across the PDV and TSP, respectively. However, respective contributions of energy metabolites to net energy release across the PDV and TSP were highly variable among treatments and did not follow the same pattern of changes in DMI.

Effects of forage intake level on nitrogen net flux by portal-drained viscera of mature sheep with abomasal infusion of an amino acid mixture

“…Diet digestibility and N balance Diet digestibility has been described in detail (EL-Sabagh et al, 2013). Increasing DMI level induced linear increases in fecal and urinary N losses and N retention along with a quadratic effect of DMI on urinary total N and N balance (Table 2).…”

“…Blood and plasma flows with the basal diet are presented in detail in the companion paper (EL-Sabagh et al, 2013). Blood and plasma flows of the portal vein increased linearly (P , 0.05) with increasing DMI of the basal diet (Table 4).…”

“…Surgical procedures and dietary regimens have been described (EL-Sabagh et al, 2013). Briefly, four Suffolk mature sheep (61.4 6 3.6 kg BW, 4.1 6 1.9 years old) were surgically fitted with abomasal cannulae and catheters in the hepatic portal vein, mesenteric vein and caudal aorta.…”

“…Feed and feces sampling and analysis for DM, organic matter (OM) and NDF have been described previously (EL-Sabagh et al, 2013). Urine was collected into plastic collection vessels containing 100 ml of 10 N H 2 SO 4 to inhibit ammonia volatilization.…”

Spineless cactus associated with Tifton hay or sugarcane bagasse may replace corn silage in sheep diets

“…It is likely that the increased flow of nutrients in the tissues of animals fed with TH has favored muscle anabolism and increased the carcass weight and empty body weight of the animals (EL-Sabagh et al 2013;Riaz et al 2014). In fact, it was observed that there was a greater deposition of muscle (kg) and fat (kg) in the loin of sheep fed with FT. Means in the same row followed by different letters differ statistically (P < 0.05)…”