Leg weakness in pigs. II. Litter differences in leg weakness, skeletal lesions, joint shape and exterior conformation

Investigations were carried out concerning possible litter differences in locomotory ability and exterior conformation, and possible litter and sire group differences in the occurrence of skeletal lesions and in joint shape. The animals were from a breed experiment involving 6 litters, 8 feeding experiments involving 64 litters, and a selection experiment totalling 70 litters and 25 sire groups distributed in 3 lines. One hundred and twenty-one out of 285 P values for litter or sire group differences were statistically significant (P < 0.05). This shows, with reservations concerning the possibility that different environmental conditions up to 20 kg live weight may have produced a litter effect on pigs from the breed and feeding experiments, that heredity plays a significant part in the leg weakness complex. It seems justified to conclude that it partly is the inheritance of certain joint shapes and exterior conformational features, which influence the degree of joint lesions and locomotory ability and give rise to litter differences. This gives the theoretical possibility of selecting for more lasting joints and better locomotory ability using criteria based on joint shape and exterior conformation.     

Osteochondrosis and arthrosis in pigs. I. Incidence in animals up to 120 kg live weight

Joint and bone lesions in growing pigs are described on the basis of post-mortem examination of 341 gilts, boars or castrates from 10 to 120 kg live weight, and 869 separate bones from pigs between 80 and 115 kg live weight at slaughter. No evidence of rickets or generalized osteodystrophia fibrosa was found. Lesions occurred in both sexes. The typical osteochondral lesions were most often symmetrical, occurred at certain sites in joints and epiphyseal plates and were most obvious in the elbow and stifle joint, and in the distal epiphyseal plate of the ulna. Lesions of varying degree could be demonstrated in most pigs at 90–100 kg live weight. The use of the diagnosis osteochondrosis is suggested for local primary non-inflammatory disturbances which lead to a failure of endochondral ossification in joint cartilage as well as in epiphyseal plates. The diagnosis arthrosis is used when the superficial layer of the joint cartilage is affected. Investigations of the early changes in the medial condyle of the femur suggest that the osteochondral lesions start in the deep layers of the joint cartilage. Arthrosis occurred frequently in the lumbar intervertebral joints of Norwegian pigs. Otherwise the lesions appeared to be identical with those described from other countries.     

Reduced dietary protein level influences the free amino acid and gene expression profiles of selected amino acid transceptors in skeletal muscle of growing pigs

This study was conducted to evaluate the effect of reduced dietary protein level on growth performance, muscle mass weight, free amino acids (FAA) and gene expression profile of selected amino acid transceptors in different fibre type of skeletal muscle tissues (longissimus dorsi, psoas major, biceps femoris) of growing pigs. A total of 18 cross‐bred growing pigs (Large White × Landrace × Duroc) with initial body weight (9.57 ± 0.67 kg) were assigned into three dietary treatments: 20% crude protein (CP) diet (normal recommended, NP), 17% CP diet (low protein, LP) and 14% CP diet (very low protein, VLP). The results indicated improved feed‐to‐gain ratio was obtained for pigs fed LP and NP diets (p < 0.01), while the pigs fed VLP diet showed the worst growth performance (p < 0.01). There was no significant difference in the weights of longissimus dorsi and psoas major muscle between LP and NP groups (p > 0.05). Majority of the determined FAA concentration of LP group were greater than or equal to those of NP group in both longissimus dorsi and psoas major muscle (p < 0.01). Further, the mRNA expression levels of sodium‐coupled neutral amino acid transceptor 2, L‐type amino acid transceptor 1 and proton‐assisted amino acid transceptors 2 were higher in skeletal muscle tissue in LP group compared to those of the pigs fed NP or VLP diet. These results suggested that reduced dietary protein level (3 points of percentage less than recommended level) would upregulate the mRNA expression of amino acid transceptors to enhance the absorption of FAA in skeletal muscle of growing pigs. There seems to be a relationship between response of AA transceptors to the dietary protein level in skeletal muscle tissue of different fibre type. To illustrate the underlying mechanisms will be beneficial to animal nutrition.