Relationship of Birth Weight with the Size, Number and Proportion of Fibres in the Pig Semitendinosus Muscle

Decellularised plant scaffolds facilitate porcine skeletal muscle tissue engineering for cultivated meat biomanufacturing

Cultivated meat (CM) offers a sustainable and ethical alternative to conventional animal agriculture, involving cell maturation in a controlled environment. To emulate the structural complexity of traditional meat, the development of animal-free and edible scaffolds is crucial, providing vital physical and biological support during tissue development. The aligned vascular bundles of the decellularised asparagus scaffold were selected to facilitate the attachment and alignment of murine myoblasts (C2C12) and porcine adipose-derived mesenchymal stem cells (pADMSCs). Muscle differentiation was assessed through immunofluorescence staining with muscle markers, including Myosin heavy chain (MHC), Myogenin (MYOG), and Desmin. The metabolic activity of Creatine Kinase in C2C12 differentiated cells significantly increased compared to proliferated cells. Quantitative PCR analysis revealed a significant increase in Myosin Heavy Polypeptide 1 (MYH1) and MYOG expression compared to Day 0. These results highlight the application of decellularised plant scaffold (DPS) as a promising, edible material conducive to cell attachment, proliferation, and differentiation into muscle tissue. To create a CM prototype with biological mimicry, pADMSC-derived muscle and fat cells were also co-cultured on the same scaffold. The co-culture was confirmed through immunofluorescence staining of muscle markers and LipidTOX staining, revealing distinct muscle fibres and adipocytes containing lipid droplets respectively. Texture profile analysis conducted on uncooked CM prototypes and pork loin showed no significant differences in textural values. However, the pan-fried CM prototype differed significantly in hardness and chewiness compared to pork loin. Understanding the scaffolds' textural profile enhances our insight into the potential sensory attributes of CM products. DPS shows potential for advancing CM biomanufacturing.

Differences in muscle characteristics of piglets related to the sow parity

da Silva, A., Dalto, D., Lozano, A., de Oliveira, E., Gavioli, D., de Oliveira, J., Jamile, Romero, N. and da Silva, C. 2013. Differences in muscle characteristics of piglets related to the sow parity. Can. J. Anim. Sci. 93: 471–475. Two hundred forty-three piglets were obtained from 81, 1st through 7th parity sows to determine the influence of sow's parity on piglets’ myogenesis. Those piglets weighing close to or equal to the average weight of their litter were sacrificed, and their semitendinosus muscles were collected to determine the secondary muscle fiber number, area and weight. The number of secondary muscle fibers was correlated with muscle weight (P<0.05; 0.39) and muscle area (P<0.001; 0.63), and muscle area and weight were also correlated (P<0.001; 0.64). Weights of piglets at birth had a correlation with number of muscle fibers (P<0.05; 0.39), muscle area (P<0.001; 0.54) and muscle weight (P<0.001; 0.73). The piglets’ birthweights and muscle weight, muscle area and muscle secondary fiber numbers increased quadratically as parity increased (R 2=0.56, 0.36, 0.44, 0.64 and 0.54; P<0.05, respectively). The results of this study indicate that parity influences the pre-natal development of piglets and that the best muscle characteristics of piglets born from 3rd and 4th parity sows were responsible for their higher weight at birth.

Intra-uterine growth retardation affects birthweight and postnatal development in pigs, impairing muscle accretion, duodenal mucosa morphology and carcass traits

The present study investigated the occurrence of intra-uterine growth retardation (IUGR) in newborn (n = 40) and 150-day-old (n = 240) pigs of different birthweight ranges (high, HW: 1.8–2.2 kg; low, LW: 0.8–1.2 kg) from higher-parity commercial sows and its impact on their subsequent development and carcass traits in a Brazilian commercial production system. HW newborn pigs had heavier organs than LW pigs (P < 0.01), and all brain : organ weight ratios were higher (P < 0.01) in LW compared with HW offspring, providing strong evidence of IUGR in the LW piglets. HW pigs had higher bodyweights and average daily gain (ADG) in all phases of production (P < 0.05), but ADG in the finisher phase was similar in both groups. Additionally, LW newborn and 150-day-old pigs showed a lower percentage of muscle fibres and a higher percentage of connective tissue in the semitendinosus muscle, greater fibre number per mm2 and a lower height of the duodenal mucosa (P < 0.05). On the other hand, HW pigs had higher hot carcass weight, meat content in the carcass and yield of ham, shoulder and belly (P < 0.01). Hence, lower-birthweight piglets may suffer from IUGR, which impairs their growth performance, muscle accretion, duodenal mucosa morphology and carcass traits.

Intrauterine crowding impairs formation and growth of secondary myofibers in pigs

There are indications that intrauterine crowding may cause intrauterine growth retardation with the possibility of an impaired myofiber hyperplasia. The aim of the study was to confirm this by generating large differences in uterine space using sows that were unilaterally hysterectomized-ovariectomized (HO; crowded) or unilaterally oviduct ligated (OL; non-crowded). In the study, seven HO and seven OL Swiss Large White third parity sows were used. At farrowing, litter size and litter birth weight were determined. Subsequently, within each litter two male and two female progenies each with the respectively lowest (L) and highest (H) birth weight were sacrificed. Internal organs and brain were weighed, and longissimus (LM) and semitendinosus muscle (SM) samples were collected. Histological analyses were performed in both muscles using mATPase staining after preincubation at pH 4.3 and 10.2. Myosin heavy chain (MyHC) polymorphism was determined in the LM by means of SDS-PAGE. The number of piglets born alive was similar in both sow groups, but litter size expressed per uterine horn was lower (P < 0.05) in OL than HO sows. Consequently, OL progeny were markedly heavier (P < 0.01). Regardless of gender, the organs, the brain and the SM were heavier (P < 0.001) in OL and H compared with HO and L offspring, respectively. Compared with HO pigs, the SM of OL offspring tended (P < 0.1) to have more myofibers, which were of larger (P < 0.05) size. However, myofiber density appeared to be lower (P < 0.1) in the SM of OL than HO pigs. The impact of birth weight on myofiber characteristics was limited to the lower (P < 0.05) myofiber density in the SM and the larger (P < 0.01) myofiber size in the light portion of the SM of H than L offspring, whereas myofiber hyperplasia did not differ between birth weight categories. The SM, but not the LM, of male offspring had a greater (P < 0.05) myofiber density. This did not affect total SM myofiber number. The relative abundance of fetal and type I MyHC in the LM was lower (P < 0.05) and that of type II MyHC was greater (P < 0.001) in OL than HO pigs. The current data suggest that regardless of birth weight and gender, in the LM and SM of individuals born from a crowded environment, not only hyperplasia but also hypertrophy of myofibers is impaired and their maturity seems delayed.