Impact of seasonal thermal stress on physiological and blood biochemical parameters in pigs under different dietary energy levels

Abstract

The present study was formulated to find out the status of important season related thermal stress biomarkers of pure-bred (Hampshire) and crossbred (50% Hampshire × 50% local) pigs under the agro-climatic condition of Assam State, India. The experiment was also aimed to study the role of different level of energy ration (110, 100, and 90% energy of NRC feeding standard for pig) in variation of physiological and biochemical parameters in two genetic groups of pigs in different seasons. The metabolizable energy value were 3260, 2936.5, and 3585.8 kcal/kg in grower ration and 3260.2, 2936.6, and 3587 kcal/kg in finisher ration for normal energy (NE), low energy (LE) and high energy (HE), respectively. Both the genetic group of animals were housed separately under intensive system of management. Each pen was measuring 10' × 12' along with an outer enclosure. Six weaned piglets (almost similar body weight of average 10.55 kg) of each group were kept in a separate pen. However, after attainment of 35 kg body weight, the animals of a group were divided in two pens of three animals each. The present experiment indicated that average ambient temperature during summer months (27.33-29.51 °C) was above the comfort zone for pigs (22 °C). The significantly (P < 0.01) higher relative humidity (RH) (%) was recorded in outdoor environment (87.26-91.10%) and in the morning time (86.60-91.10%). The temperature humidity index (THI) during the study period was found to be indicative of thermal stress to the experimental animals during summer (79.55-82.56). Physiological parameters viz., respiration rate (RR) and rectal temperature (RT) were significantly (P < 0.01) higher in summer season (43.75-72.12 breaths/min. and 102.29-103.23 °F) and non-significantly higher values were recorded in Hampshire pigs. It was also found that the significantly (P < 0.01) lower RR as well as RT was recorded in the pigs fed with high energy (HE) ration during summer season. Serum triiodothyronine (T) and thyroxine (T) concentrations were significantly (P < 0.01) lower during summer, while both the genetic groups showed significantly (P < 0.01) higher concentration of serum cortisol during summer season. It was also observed that thyroid hormone and cortisol concentrations were maintained in groups of pig fed vegetable oil incorporated HE diet during summer. From the present study, it is found that the increasing the energy level of the ration might be helpful to minimize the effects of thermal stress during summer.

Thermal stress-related physiological, behavioral, and serum biochemical responses in indigenous pigs adapted to Eastern Himalayan region

“…Stress triggers the hypothalamus, which enhances respiratory activity to speed up heat escape from the body through respiratory evaporation (37). In animals, there is a correlation between respiration rate and the surrounding temperature and microenvironments (28) or a THI of 73 (30). In the present study, RR of indigenous and crossbred pigs was within the normal range, that is, 15-30 breaths per minute as reported by Silanikove (30); however, it was higher than the normal range during heat stress in Hampshire, suggesting the susceptibility to heat stress.…”

Maternal and fetal thyroid dysfunction following porcine reproductive and respiratory syndrome virus2 infection

“…Feed restriction for as little as 24 h has been shown to cause a significant decrease in the circulating T3 and T4 levels in swine [28]. There is also established interplay between feed intake and ambient temperatures [20,29,30] as well as additional alterations following adaptation to new diets [31]. Given that the control and infected gilts originated from the same genetic nucleus farm, the apparent susceptibility of the thyroid hormone system to environmental conditions leads us to posit that the observed pre-challenge difference likely stems from minor differences in the conditions between the facilities in which these two groups were housed.…”

Multivariate analysis of body weight, morphometric and thermo-physiological traits of indigenous pigs under tropical conditions

“…The respiratory rate and rectal temperature of the present study were lower than the values of 43.75-72.12 breaths/min. and 39.05 °C-39.57 °C obtained in pigs reared in India (Pathak et al, 2018). The differential values could be as a result of varying genetic groups, weather conditions and management practices.…”