Effect of a single nucleotide polymorphism in the growth hormone secretagogue receptor (GHSR) gene on growth rate in pigs

Association analysis of the sorting nexin 29 (SNX29) gene copy number variations with growth traits in Diannan small-ear (DSE) pigs

SNX29 is a potential functional gene associated with meat production traits. Previous studies have shown that SNX29 copy number variation (CNV) could be implicated with phenotype in goats. However, in Diannan small-ear (DSE) pigs, the genetic impact of SNX29 CNV on growth traits remains unclear. Therefore, this study investigated the associations between SNX29 CNVs (CNV10810 and CNV10811) and growth traits in 415 DSE pigs. The results revealed that the CNV10810 mutation was significantly associated with backfat thickness in DSE pigs at 12 and 15 months old (P < 0.05), while the CNV10811 mutation had significant effects on various growth traits at 6 and 12 months old, particularly for body weight, body height, back height and backfat thickness (P < 0.05 or P < 0.001). In conclusion, our results confirm that SNX29 CNV plays a role in regulating growth and development in pigs, thus suggesting its potential application for pig breeding programmes.

Divergence of Liver Lipidomes in Tibetan and Yorkshire Pigs Living at Different Altitudes

The Tibetan pig is a characteristic breed of the Qinghai-Tibet Plateau with distinct physiological and meat quality attributes. The liver lipid profile can offer an important perspective to explore the uniqueness of Tibetan pigs. A quantitative comparison of liver lipidomes revealed significant differences in the lipid profiles between Tibetan and Yorkshire pigs raised at different altitudes. The abundance of lipids in the livers of pigs raised at a high altitude was higher than that of pigs raised at a lower altitude, whereas the abundance of lipids in the livers of Yorkshire pigs was higher than that of Tibetan pigs raised at the same altitude. Of the 1101 lipids identified, 323 and 193 differentially abundant lipids (DALs) were identified in the pairwise comparisons of Tibetan and Yorkshire pigs raised at different altitudes, respectively. The DALs of Tibetan pigs consisted mainly of 161 triglycerides, along with several acylcarnitines, represented by carnitine C2:0, and significant changes in the abundance of some phospholipids. The DALs of Yorkshire pigs were more complex, with significant increases in the abundance of triglycerides, cholesteryl esters, and free fatty acids, and decreases in the abundance of some phospholipids. This research provides strong theoretical and data support for the high-quality development of the highland livestock industry.

Differential Diagnosis of the Short IGF-I-Deficient Child with Apparently Normal Growth Hormone Secretion

The current differential diagnosis for a short child with low insulin-like growth factor I (IGF-I) and a normal growth hormone (GH) peak in a GH stimulation test (GHST), after exclusion of acquired causes, includes the following disorders: (1) a decreased spontaneous GH secretion in contrast to a normal stimulated GH peak ("GH neurosecretory dysfunction," GHND) and (2) genetic conditions with a normal GH sensitivity (e.g., pathogenic variants of GH1 or GHSR) and (3) GH insensitivity (GHI). We present a critical appraisal of the concept of GHND and the role of 12- or 24-h GH profiles in the selection of children for GH treatment. The mean 24-h GH concentration in healthy children overlaps with that in those with GH deficiency, indicating that the previously proposed cutoff limit (3.0-3.2 μg/L) is too high. The main advantage of performing a GH profile is that it prevents about 20% of false-positive test results of the GHST, while it also detects a low spontaneous GH secretion in children who would be considered GH sufficient based on a stimulation test. However, due to a considerable burden for patients and the health budget, GH profiles are only used in few centres. Regarding genetic causes, there is good evidence of the existence of Kowarski syndrome (due to GH1 variants) but less on the role of GHSR variants. Several genetic causes of (partial) GHI are known (GHR, STAT5B, STAT3, IGF1, IGFALS defects, and Noonan and 3M syndromes), some responding positively to GH therapy. In the final section, we speculate on hypothetical causes.

Comparative Transcriptome Analyses of Longissimus thoracis Between Pig Breeds Differing in Muscle Characteristics

The two breeds, Mashen (MS; a northern China breed) and Large White (LW; a western lean breed) pigs, show important phenotypic differences in growth, adaptability, intramuscular fat (IMF) content, and energy metabolism since early developmental stage. The main aim of this study was the evaluation of longissimus thoracis muscle transcriptome profile of both genetic types to identify genes, pathways responsible for their differentiated phenotype. Longissimus thoracis of MS and LW pigs were sampled at 0 day (early stage), 90 days (middle stage), and 180 days (later stage) after birth. A total of 3,487 differentially expressed genes (DEGs) were identified at the three time points. Sample clustering analysis revealed the slower growth rate of MS than LW pigs. Gene expression pattern analysis revealed that multicellular organism growth genes (GHSR, EZR, FOXS1, DRD2, SH3PXD2B, CSF1, and TSHR) were involved in the fast growth rate of LW pigs at early stage. Furthermore, DEGs (ACACA, ACSF3, OXSM, CBR4, and HSD17B8) functionally related to fatty acid synthesis revealed that IMF accumulation occurred around 90 and up to 180 days. These DEGs provided valuable resource to study the phenotypic difference in longissimus thoracis muscle between MS and LW pigs.