Partitioning of heat production in growing pigs as a tool to improve the determination of efficiency of energy utilization

Abstract

In growing pigs, the feed cost accounts for more than 60% of total production costs. The determination of efficiency of energy utilization through calorimetry measurements is of importance to sustain suitable feeding practice. The objective of this paper is to describe a methodology to correct daily heat production (HP) obtained from measurements in respiration chamber for the difference in energy expenditure related to physical activity between animals. The calculation is based on a preliminary published approach for partitioning HP between HP due to physical activity (AHP), thermic effect of feeding (TEF) and basal metabolic rate (fasting HP; FHP). Measurements with male growing pigs [mean body weight (BW): 115 kg] which were surgically castrated (SC), castrated through immunization against GnRH (IC), or kept as entire male (EM) were used as an example. Animals were fed the same diet ad-libitum and were housed individually in two 12-m3 open-circuit respiration chambers during 6 days when fed ad-libitum and one supplementary day when fasted. Physical activity was recorded through interruption of an infrared beam to detect standing and lying positions and with force transducers that recorded the mechanical force the animal exerted on the floor of the cage. Corrected AHP (AHPc), TEF (TEFc), and HP (HPc) were calculated to standardize the level of AHP between animals, assuming that the ratio between AHPc and ME intake should be constant. Inefficiency of energy utilization (sum of AHPc and TEFc) was lower than the inefficiency estimated from the slope of the classical relationship between HPc and ME intake but was associated with higher requirements for maintenance. Results indicate that EM pigs had higher FHP but lower TEFc than IC and SC pigs. These results agree with the higher contents in viscera of EM pigs that stimulate their basal metabolic rate and with the reduced utilization of dietary protein to provide energy for maintenance energy requirements and fat deposition (FD).

Effect of high dietary fat content on heat production and lipid and protein deposition in growing immunocastrated male pigs

“…However, it is difficult to discriminate between IC and growth effect. Comparing with the literature, it can be hypothesized that PD was likely increased due to growth, but not affected by IC, as Labussière et al (2013) showed similar PD in IC and EM pigs 5 weeks after V2 (and superior to barrows). On the other hand, LD seems to be increased not only with growth, but also due to IC.…”

“…A numerical decrease in fasting HP was even noted, which illustrates the important changes in the physiology and metabolism due to IC. Higher body fatness (van Milgen et al, 1998) and changed hormonal status after IC (castrate v. male, Labussière et al, 2013) have both been associated with decreased basal metabolic rate. In the present study, there was also no effect of IC/growth on total thermic effect of feeding (as % ME).…”

“…Consequently, energy gain after V2 was more pronounced than expected from ME intake change only. Nevertheless, Labussière et al (2013) have shown that IC pigs have higher total thermic effect of feeding than EM due to higher feed intake and because more dietary protein is used as a source of energy with a low energetic efficiency for lipogenesis ).…”

Effect of inflammation stimulation on energy and nutrient utilization in piglets selected for low and high residual feed intake

“…time of intake and ingested quantity) and physical characteristics of the gas in the chamber were used to calculate the components of HP according to the modeling approach of van Milgen et al (1997). Parameters of the differential equations for gas concentrations in the respiration chamber involved in the model were estimated using the R software (Labussière et al, 2013). The HP due to physical activity (AHP), HP due to feed intake (short-term thermic effect of feeding, TEF s ) and HP due to resting metabolism (RHP) were calculated from respective volumes of O 2 consumption and CO 2 production according to the Brouwer equation (Brouwer, 1965), excluding urinary N losses and CH 4 production.…”

Body size, spontaneous activity and thermogenesis effects on energy expenditure: an introduction to a topic on energy metabolism

“…Dr Sarafian (from the laboratory of Dr Dulloo) described a new approach to perform standardized tests for assessing human variability in the energy cost of low-intensity isometric work that is comparable to daily life activities (Sarafian et al, 2013). Etienne Labussière described the method used in his laboratory to deal with this question in large farm animals such as white pigs (Labussiere et al, 2013), and Jan B van Klinken described the most advanced procedures for rats and mice and compared their robustness in relation to the frequency of data acquisition and quality of the activity signal (van Klinken et al, 2013). In his review, John Speakman developed an extensive section on physical activity in which he discussed the various issues related to this question (including treadmill running) and surveyed the most significant published works (Speakman, 2013).…”