Estimation of genetic parameter for feed efficiency and resilience traits in three pig breeds.

Recently, automatic feeders have become popular for collecting daily feed intake data in the pig industry, making it possible to evaluate genetic effects on feed efficiency and resilience traits, expressed as day-to-day fluctuations in feeding records. This study aimed to understand the influence of genetic factors on feed efficiency traits, including residual intake and BW gain (RIG), and resilience traits, as well as to compare the differences in genetic parameter estimates among three purebred pig breeds. A total of 6 103 pigs from three breeds (Large White: 1 193 pigs, Landrace: 3 010 pigs, and Duroc: 1 900 pigs) were raised in a specific pathogen-free environment. The growth and feed intake records during the testing period were obtained using automatic feeders, and the average daily gain (ADG) and average feed intake (AFI) were calculated. Feed conversion ratio (FCR), residual feed intake (RFI), residual gain, and RIG were calculated as feed efficiency traits, and the log-transformed variance of deviation for the daily feed intake (LnVar_FI), daily occupation time (LnVar_OC), and the daily number of visits to the feeder (LnVar_VT) was calculated as resilience traits. After estimating the genetic parameters for each breed, a meta-analysis was performed to obtain the weighted mean of heritability estimates (hm2) and genetic correlation estimates (GCm) for the three breeds. The hm2 were moderate and ranged from 0.31 to 0.39 for feed efficiency traits and 0.31 to 0.40 for resilience traits, and there were no significant differences in heritability estimates among the three breeds except for AFI, RFI, and RIG. For feed efficiency traits, the FCR and RIG showed favourably moderate GCm with AFI (0.29 and -0.33, respectively) and ADG (-0.39 and 0.31, respectively). For resilience traits, the LnVar_FI and LnVar_VT showed favourably low to moderate GCm with FCR (0.33 and 0.28, respectively) and RIG (-0.37 and 0.28, respectively), and there were no genetic relationships of LnVar_OC with FCR and RIG (the absolute value of GCm was 0.01). There was no significant difference in the genetic correlation estimates among the three breeds for feed efficiency and resilience traits. Our results suggest that feed efficiency and resilience traits were heritable, and resilience traits showed favourable or no genetic correlation with feed efficiency traits. In addition, the influence of genetic factors on feed efficiency and resilience traits could be the same among breeds.

Jejunal granuloma associated with an argyrophilic gram-negative non-segmented filamentous bacterium in a Holstein cow.

A length of intussuscepted jejunum, associated with a granuloma, was removed surgically from a 35-month-old Holstein cow. Microscopically, the granuloma consisted of multifocal aggregates of macrophages, epithelioid cells and occasional multinucleated giant cells within the lamina propria. Numerous argyrophilic, gram-negative, periodic acid Schiff-negative, non-segmented, long filamentous bacteria (2-17 microm in length, 0.1-0.3 microm in diameter) were detected in the cytoplasm of the epithelioid cells. The bacteria were localized to the granulomatous lesions. Comparative 16S rDNA gene sequencing analysis revealed that the organism was an unpublished species (accession number AB472332). This argyrophilic non-segmented filamentous bacterium appears to have been the cause of multifocal granulomatous jejunitis accompanied by intestinal intussusception in this cow.

Defective terminal differentiation and hypoplasia of the epidermis in mice lacking the Fgf10 gene.

Here, we characterized the skin and hair phenotype of mice lacking the fibroblast growth factor 10 gene (Fgf10), a newly identified member of the fibroblast growth factor family. Histological examination of Fgf10(-/-) newborn mouse skin revealed abnormalities in epidermal morphogenesis. The number of proliferating cells in the basal layer was decreased, the granular layer was hypoplastic and lacked distinctive keratohyaline granules and tonofibrils. The expression of loricrin, a marker of epidermal differentiation, was dramatically reduced. Despite the presence of Fgf10 transcripts in normal hair follicles, abnormalities of hair development were not observed in Fgf10(-/-) skin. These data suggest that Fgf10 is required for embryonic epidermal morphogenesis but is not essential for hair follicle development.

Molecular analysis of external genitalia formation: the role of fibroblast growth factor (Fgf) genes during genital tubercle formation.

The molecular mechanisms underlying the development of the external genitalia in mammals have been very little examined. Recent gene knockout studies have suggested that the developmental processes of its anlage, the genital tubercle (GT), have much in common with those of limb buds. The Fgf genes have been postulated as regulating several downstream genes during organogenesis. Fgf8 was expressed in the distal urethral plate epithelium of the genital tubercle (GT) together with other markers such as the Msx1, Fgf10, Hoxd13 and Bmp4 expressed in the mesenchyme. To analyze the role of the FGF system during GT formation, an in vitro organ culture system was utilized. It is suggested that the distal urethral plate epithelium of GT, the Fgf8-expressing region, regulates the outgrowth of GT. Ectopic application of FGF8 beads to the murine GT induced mesenchymal gene expression, and also promoted the outgrowth of the GT. Experiments utilizing anti-FGF neutralizing antibody suggested a growth-promoting role for FGF protein(s) in GT outgrowth. In contrast, despite its vital role during limb-bud formation, Fgf10 appears not to be primarily essential for initial outgrowth of GT, as extrapolated from Fgf10(-/-) GTs. However, the abnormal external genitalia development of Fgf10(-/-) perinatal mice suggested the importance of Fgf10 in the development of the glans penis and the glans clitoridis. These results suggest that the FGF system is a key element in orchestrating GT development.

The effects of ranitidine and cysteamine on intestinal metaplasia induced by X-irradiation in rats.

The influence of ranitidine and cysteamine on intestinal metaplasia was examined in 7-month-old male Crj: CD (SD) rats. At the age of 5 weeks, the animals were treated with 10 Gy doses of X-rays at 3-day intervals up to a total of 20 Gy in the gastric region, and 6 months after irradiation, the rats received either ranitidine (0.02% in diet) or cysteamine (0.1% in drinking water) for 2 months. The incidence and number of intestinal metaplasia with alkaline phosphatase-positive foci in rats given X-rays and cysteamine (group 4) were significantly low compared with those in rats given X-rays and ranitidine (group 3) (p less than 0.01). In both the pyloric and the fundic gland mucosae, the average numbers of type C metaplasia (intestinal crypts with Paneth cells) and total numbers of metaplastic foci in rats of group 3 were much higher than those in group 4 (P less than 0.05). The present results showed that the occurrence of intestinal metaplasia was significantly increased after administration of ranitidine and decreased by cysteamine.