Effects of an immune stimulant, inactivated Mycobacterium phlei, on the growth performance as well as meat quality of fattening pigs

Abstract

Inactivated mycobacterium phlei (M. phlei) is well known for its immune-stimulatory functions in humans and livestock, but less information is available about the influence on meat quality of pigs when used as a feed additive. This study was designed to evaluate the effects of inactivated M. phlei on growth performance as well as meat quality of fattening pigs. A total of 240 cross-bred pigs ([Landrace × Yorkshire] × Duroc) with initial body weight of 80.14 ± 0.29 kg were randomly allocated to five treatments, each of which consisted of eight replicates with 6six pigs per replicate. The basal diet supplemented with five levels of inactivated M. phlei preparations (0, 3.5 × 10 [0.1% w/w], 7 × 10 [0.2%], 1.4 × 10 [0.4%] or 2.1 × 10 [0.6%] colony-forming units/kg) was respectively fed to the control group and four treatment groups for 30 days. Adding 0.4% of inactivated M. phlei to diet increased the average daily feed intake and average daily gain of pigs. Importantly, intramuscular fat percentage in the Longissimus dorsi (LD) was increased by feeding diet containing 0.2%, 0.4% and 0.6% of inactivated M. phlei, despite the pH value, drip loss, cooking loss and filter paper fluid uptake not being influenced. Analysis of the fatty acid components showed that some saturated fatty acids were decreased in LD after feeding inactivated M. phlei, but some monounsaturated fat acids (MUFAs) and polyunsaturated fatty acids were increased (PUFAs), which induced the total contents of MUFAs and PUFAs were improved. RT-PCR assay revealed that feeding inactivated M. phlei up-regulated genes implicated in fat metabolism in muscle, including ELOVL6, FASN, SCD1 and H-FABP. This study revealed that feeding inactivated M. phlei not only increased growth performance of fattening pigs, but also improved the meat quality by increasing intramuscular fat content, thus inactivated M. phlei probably has high utilization value in modern pig production.

Chromatographic Methods for Evaluation of the Amino Acid and Fatty Acid Compositions Related with Pork Quality

“…Fatty acid analysis of the Longissimus dorsi showed a slight decrease in saturated and an increase in monounsaturated and polyunsaturated fatty acids. At the same time, an improvement in the quality of meat was observed with an increase in the content of intramuscular fat due to the inactivation of some genes [96].…”

“…Several other authors have studied ways to improve the quality and oxidative stability of pork using nutritional factors [92][93][94][95][96][97].…”

“…Zhong, J.-F. et al (2018) [96] fed Landrace x Yorkshire x Duroc hybrids for 30 days with a probiotic complex consisting of inactivated bacteria of the genus Mycobacterium phlei, which has immune-stimulating properties. Fatty acid analysis of the Longissimus dorsi showed a slight decrease in saturated and an increase in monounsaturated and polyunsaturated fatty acids.…”

Research progress into the application of Mycobacterium phlei in veterinary medicine

“…Some studies have found that M. phlei regulates animal growth. Zhong et al (2018) added different levels of inactivated M. phlei preparations to the diets of fattening pigs and determined the average daily feed intake and average daily weight gain of pigs after 30 days. These authors also determined the intramuscular fat content, pH, drip loss, cooking loss and filter paper fluid uptake of Longissimus dorsi in pigs and found that feeding the inactivated M. phlei preparations decreased the contents of some saturated fatty acids in fattening pigs.…”