The effects of dietary reduced mineral elements and coated cysteamine supplementation on bacterial diversity in the ileum of finishing pigs.

This study was conducted to investigate the effects of different levels of dietary partial MEs and coated cysteamine (CC) supplementation on gut microbiota in finishing pigs. Results showed that whittling down dietary partial MEs (Cu, Fe, Zn, Mn) by 20% and 40% had little effect on the microbial diversity, community structure, and bacterial relative abundance in the ileum of finishing pigs. Supplementation with 1,600 mg/kg CC also had no obvious effect on the microbial diversity, community structure, and bacterial relative abundance in the finishing pig ileum when fed diets with a normal MEs level. However, the abundance of Peptostreptococcaceae, Pasteurella, and Pasteurella_aerogenes was higher, and the abundance of Actinobacillus_minor was lower in the 20% ME reduction diet treatment than that in the 20% ME reduction with 1,600 mg/kg CC diet group (p < 0.05). In conclusion, our results suggested that there is no obvious effect on gut microbiota when dietary partial MEs are reduced by 20% or 40%, which indicates the feasibility of reducing dietary partial MEs by 20% or 40% in finishing pigs. Supplementation with CC changed the relative abundance of some bacteria related to opportunistic pathogenicity in the finishing pig ileum when were fed a 20% ME reduction diet.

[Chromosomal studies of germ cells in diploid and polyploid fish produced by distant crossing].

By observing the chromosomal spreads of germ cells and tissue sections, we studied the chromosomal spreads of germ cells in diploid and polyploid fish produced by distant crossing. The samples covered the second generation of hybrids of red crucian carp (Carassius auratus red var.) (female) x common carp (Cyprinus carpio) (male) (2n = 100) (F2), allotetraploid hybrids of red crucian carp (female) x common carp (male)(4n = 200), triploid hybrids of gold fish (female)x allotetraploid (male) (3n = 150), the second generation of the gynogenetic progeny of allotetraploid hybrids (G2) (2n = 100), and the common carp (2n = 100) used as a control. The results demonstrated that chromosomal number of spermotogonia in common carp was equal to that of their somatic cell (2n = 100), while the chromosomal number of germ cells in diploid hybrid fish and polyploid hybrid fish had doubled obviously, and the frequent of chromosomal doubling in spermotogonia of F2 appeared especially high, accounting for 21.6% of all examined chromosomal spreads, which provided directly cytological evidence for the production of unreduced diploid gametes in F2 and also indicated that distant crossing was an important factor to lead to chromosomal doubling in germ cell. This research had important significance in studies on the formation of polyploidy fish and fish breeding.