Genetic landscape of bovine genome attracts a lot of attention in recent years. This is due to the complexity of genomic selection task solution, i.e. the use of multilocus genotypes in order to simplify and hasten breeding. Accumulated data show that there is high evolutionary speed of different genetic elements and also they have structure functional polymorphism intensity (L. Chen et al., 2017). It was shown that interspersed repeats account for about 50 % of nucleotide sequence of the bovine genome (R.L. Tellam et al., 2009). Also it was found that some of the interspersed repeats cluster into conservative domains along the bovine genome due to joint localization (D.L. Adelson et al., 2009). The characteristics of domain distribution are still not fully studied despite the fact that it is very important to identify conservative and variable domains throughout the bovine genome to solve traditional tasks of their genetic resources management and controlling. In this work domain distribution of mobile genetic elements and their products of recombination in nucleotide sequences of 13,436,028 nucleotides of bovine chromosome 1 were analyzed by means of Repeat Masker mobile genetic elements database and Integrated Genome Browser software. It was revealed that the most prevalent types throughout analyzed region are SINE/tRNA-Core-RTE, LINE/RTE-BovB, LINE/L1 and LTR/ERV. Their joint localization in bovine genome has complicated structure. The most common pairwise clusters are SINE and LINE, SINE/tRNA-Core-RTE and LTR EVR, (LTR/ERVK)/(LINE/RTE-BovB), (LTR/ERVK)/(LINE/L1). Two last pairs are the bases for such triple clusters as (LINE/RTE-BovB)/(BTLTR1)/(LINE/RTE-BovB) and (LINE/L1)/(BTLTR1J)/(LINE/L1). It should be mentioned that there is no such clustering with other retrotransposons. It was revealed that there is some certain bias of these triple clusters high density to the distal end of studied region of chromosome 1. By the means of Integrated Genome Browser software the localization of obtained triple products of recombination between LINE and LTR ERV to structural genes was analyzed. It was found that only 34 clusters are localized in 12 structural genes (other are located in intergenic space). Besides, 10 and 12 copies are located in two genes that are closely connected with the function of central nervous system in mammals, grik1 and app. The fact that 9 copies of triple gene construct (LINE/RTE-BovB)/(BTLTR1)/(LINE/RTE-BovB) are found in each of two genes and (LINE/L1)/(BTLTR1J)/(LINE/L1) had only 1 copy in grik1 and 3 copies in app, suggests that these genes are ancestral targets for such insertions and their conservations. It also should be mentioned that (LINE/L1)/(BTLTR1J)/(LINE/L1) construct was found only in these two genes but not in other 10 genes where (LINE/RTE-BovB)/(BTLTR1)/(LINE/RTE-BovB) is also located. Specific features of distribution of products of recombination between LINE and LTR ERV throughout the studied chromosome 1 area and their localization in structural genes suggest the possible...

This study evaluated the effect of three levels of digestible amino acids (DAA; 100, 107 and 114% of Cobb recommendations) on mRNA abundance of peptide (PepT1) and amino acid (AA) transporters in 480-day-old broilers during prestarter period. Jejunal mRNA levels of the PepT1 and bAT increased as DAA level increased from 100 to 114%. The expression of CAT1 mRNA in the jejunum was higher in birds fed 100% DAA diet. The transport systems BAT and yLAT1 were not affected by the dietary treatments. These results demonstrated that dietary content of protein and DAA differentially affected the expression of intestinal peptide and AA transporters to modulate absorption of peptide and AA in broilers.

The objective of this study was to evaluate effects of mash and crumble pre-starter diets on pancreatic enzyme activity, intestinal morphology, gene expression of intestinal peptide and amino acid (AA) transporters of broilers. Broilers in battery cages were assigned to different feed forms of pre-starter diet from 1 to 10 days of age. Significantly increased body weight gain (BWG), feed intake (FI) and lowered FCR were observed in birds fed crumble pre-starter diet (CPD, p < 0.05). Feed forms had no effect on whole and small intestine length, but relative intestinal length and relative small intestinal length significantly increased in the broilers fed a mash pre-starter diet (MPD, p < 0.05). Feeding CPD increased the weight of pancreas (p < 0.05), but relative weight of the pancreas was not influenced by treatments. Pancreatic protease and amylase activities significantly increased in the broilers fed CPD (p < 0.05) but the activity of lipase was not influenced. Crypt depth (CD) and villus height (VH) were higher in broilers fed CPD (p < 0.05) but villus width (VW), villus surface area (VSA) and villus height-to-crypt depth ratio (VCR) were not influenced by treatments. mRNA levels for peptide transporter 1 (PepT1), Na -independent cationic AA transporter1 (CAT1), Na -independent cationic and Na -dependent neutral AA transporter 1 (y LAT1) and Na -dependent neutral AA transporter (B AT) were lower in birds fed CPD (p < 0.05). There were no differences in mRNA abundance of Na -independent cationic and zwitterionic AA transporter (b AT) among treatments. Overall, the present data showed that feeding crumble diet during first 10 days of age, through higher FI, enhanced intestinal histomorphology, increased digestive enzyme activity is beneficial to growth performance of broilers. Indeed, dietary form can be an important factor in the expression of jejunal transporters.

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