Effect of dietary protein on growth performance, and serum biochemical index in late pregnant Hu ewes and their offspring.

The purpose of this study was to investigate the effects of different protein levels in late pregnancy on ewe and lamb growth performance, serum biochemical indexes. Thirty-three ewes (46.4 ± 1.38 kg initial weight) were randomly divided into 3 groups, with 11 ewes in each group. The protein levels of three diets formulated to provide components to meet 10.00 MJ/kg ME requirements diets were: 10.12%, 11.26%, 12.4%. Ewes were raised from the 90th day of pregnancy to the end of delivery, and the lambs were weaned at 60 days. Dietary protein levels had significant effects on blood urea nitrogen, glucose, ammonia nitrogen and triglyceride of ewes (p < 0.05). The height, chest depth, chest circumference, straight crown hip length and curved crown hip length of lambs decreased at first and then increased with the increase of protein. The body length, chest circumference, head width and head length of weaned lambs decreased at first and then increased with the increase of protein. The results showed that when the dietary protein level was increased to 12.4%, the amino acid, glucose and fat metabolism of ewes were affected. The body size development of lambs was better than 10.12% and 11.26% proteins.

The impact of lactating Hu sheep's dietary protein levels on lactation performance, progeny growth and rumen development.

This study aimed to investigate whether lactating Hu sheep's dietary protein levels could generate dynamic effects on the performance of their offspring. Twelve ewes with similar parity were fed iso-energy diets which contained different protein levels (P1: 9.82%, P2: 10.99%) (n = 6), and the corresponding offspring were divided into SP1 and SP2 (n = 12). At 60 days, half of the lambs were harvested for further study: the carcass weight (p = 0.043) and dressing percentage (p = 0.004) in the SP2 group were significantly higher than SP1. The acetic acid (p = 0.007), propionic acid (p = 0.003), butyric acid (p < 0.001) and volatile fatty acids (p < 0.001) in rumen fluid of SP2 were significantly lower than SP1. The expression of MCT2 (p = 0.024), ACSS1 (p = 0.039) and NHE3 (p = 0.006) in the rumen of SP2 was lower than SP1, while the HMGCS1 (p = 0.026), HMGCR (p = 0.024) and Na+/K+-ATPase (p = 0.020) was higher than SP1. The three dominant phyla in the rumen are Bacteroidetes, Proteobacteria and Firmicutes. The membrane transport, amino acid metabolism and carbohydrate metabolism of SP1 were relatively enhanced, the replication and repair function of SP2 was relatively enhanced. To sum up, the increase of dietary protein level significantly increased the carcass weight and dressing percentage of offspring and had significant effects on rumen volatile fatty acids, acetic acid activation and cholesterol synthesis related genes. HIGHLIGHTSIn the early feeding period, the difference in ADG of lambs was mainly caused by the sucking effect.The increase in dietary protein level of ewes significantly increased the carcass weight and dressing percentage of offspring.The dietary protein level of ewes significantly affected the volatile fatty acids (VFAs) and genes related to acetic acid activation and cholesterol synthesis in the rumen of their offspring.The membrane transport, amino acid metabolism and carbohydrate metabolism of the offspring of ewes fed with a low protein diet were relatively enhanced.The replication and repair function of the offspring of ewes fed with a high protein diet was relatively strengthened.

Effects of Dietary Energy Levels on Rumen Fermentation, Gastrointestinal Tract Histology, and Bacterial Community Diversity in Fattening Male Hu Lambs.

This study investigated rumen fermentation and histological and microbial diversity in male Hu lamb fed diets with different metabolizable energy (ME) levels (MEA, 9.17 MJ/kg, MEB, 10.00 MJ/kg, and MEC, 10.82 MJ/kg). Thirty-six male Hu lambs were randomly allotted to three treatments, and the feeding trial lasted for 67 days. Rumen fermentation results suggest that the iso-valerate had a significant effect on dietary energy level. The papillary height (PH) of rumen was the highest in the MEB group, the crypt depth (CD) was significantly increased in the duodenum and jejunum, and the villus height (VH)-to-CD ratio (VH/CD) was significantly decreased in the duodenum by increasing dietary energy levels; the VH, villus width (VW), and VH/CD also had significant differences in the ileum. 16S rRNA sequencing results showed that the operational taxonomic units (OTUs) number, the ACE, and Chao1 indices were linearly decreased by increasing dietary energy level; 24 phyla including 124 genera were identified, and the relative abundance of Papillibacter and Quinella linearly decreased by increasing the dietary energy level. Compared to MEA and MEB groups, the relative abundance of unidentified_Veillonellaceae and Anaerovibrio was significantly increased in the MEC group at the genus level. The relative abundance of the carbohydrate metabolism pathway predicted by Phylogenetic Investigation of Communities by Reconstruction of Unobserved States (PICRUSt) was linearly increased by increasing the dietary energy levels. Three metabolic pathways identified in Kyoto Encyclopedia of Genes and Genomes (KEGG) level 3 were significantly influenced as the dietary energy level increased. In summary, these results demonstrated that the dietary energy levels affected the rumen fermentation parameters, morphological structures of the gastrointestinal tract (GIT), and the composition and function of rumen microflora in male Hu sheep.

Effects of dietary energy levels on rumen fermentation, microbiota, and gastrointestinal morphology in growing ewes.

This study investigated whether dietary metabolizable energy (ME) could generate dynamical effects on rumen fermentation, gastrointestinal tract (GIT) morphology, and microbial composition of growing ewes. A total of twenty-eight female Hu lambs were randomly allotted to two treatments with different dietary ME levels: 9.17 (FEA) and 10.41 MJ/kg (FEB). These lambs were further made ready for a 67-day feeding trial. Results showed that the molar proportions of butyrate (p = .020), iso-valerate (p = .028), and valerate (p = .005) were significantly higher in the FEB group than those in the FEA group. The results of the GIT morphologic properties showed that the villus height (VH) (p = .005) was significantly higher and crypt depth was significantly deeper (CD) (p = .005) in the duodenum and that the rumen papillary height (PH) was significantly higher (p = .020) in FEB group compared with the FEA group. High-throughput sequencing results showed that 1826 operational taxonomic units (OTUs) were obtained and that the OTU number (p = .039), the ACE (p = .035), and Chao1 indices (p = .005) were lower in the FEB group. Moreover, 76 genera belonging to 21 phyla were detected in all samples; the relative abundance of Papillibacter (p = .036) and Flexilinea (p = .046) was significantly lower in the high energy group, whereas the relative abundance of unidentified Lachnospiraceae (p = .019), Acetitomaculum (p = .029), unidentified Veillonellaceae (p = .017), Anaerovibrio (p = .005), and Succinivibrio (p = .035) was significantly higher in the FEB group at the genus level. Furthermore, the relative abundance of genes and metabolic pathways were predicted by PICRUSt. The relative abundance of gene families related to carbohydrate metabolism was particularly higher (p = .027) in the FEB group. In summary, these results reveal that the dietary energy levels altered the composition and function of rumen microbiota and GIT morphology in growing female Hu sheep and provide a reference for optimizing diet formula and 10.41MJ/kg of ME level has been recommended in the growing period.

Effects of dietary energy on growth performance, carcass characteristics, serum biochemical index, and meat quality of female Hu lambs.

This study evaluated the effects of dietary energy levels on growth performance, carcass traits, meat quality, and serum biochemical of female Hu lambs. Seventy female Hu lambs (aged 4 months) were randomly allotted to 5 dietary treatments. Lambs were fed diets with 5 levels of metabolizable energy (ME): 9.17 (E1), 9.59 (E2), 10.00 (E3), 10.41 (E4), and 10.82 MJ/kg (E5). The lambs were adapted to the experimental diets for 10 d and the experiment period lasted for 60 d. Dry matter intake and feed conversion ratio linearly (P < 0.001) increased and decreased (P < 0.001), respectively, with increasing dietary ME levels. Average daily gain (ADG) linearly (P < 0.001) increased with increasing dietary ME levels, with the highest final body weight (P = 0.041) observed in E4 group. Moreover, dietary energy level was associated with linear increases in serum total protein (TP) (P < 0.001), albumin (ALB) (P = 0.017), glucose (GLU) (P = 0.004), and low-density lipoprotein cholesterol (LDLC) (P = 0.006) concentrations, and it was associated with a quadratic decrease in serum triglyceride (TG) concentration (P = 0.002). Serum ammonia concentration, which was firstly decreased and then increased, was quadratically affected by dietary ME levels (P = 0.013). Compared with E1 group, lambs in E4 group had higher (P < 0.05) live weights, carcass weights, mesenteric fat ratio, non-carcass fat ratio, and larger loin muscle area, but lower (P < 0.05) meat colour a∗ and b∗ values, and lesser (P < 0.05) C17:0, C20:0, C18:1n-9t, C18:3n-3, and n-3 polyunsaturated fatty acids (PUFA), but greater (P < 0.05) C18:3n-6 and n-6:n-3 ratios in longissimus dorsi (LD) muscle tissue, and lesser (P < 0.05) C17:0, C18:3n-3, C22:6n-3, and n-3 PUFA in the biceps femoris (BF) muscle tissue. The results demonstrated that increasing dietary energy level improved the growth performance and affected carcass traits, serum biochemical indexes, and fatty acid profiles in different muscles of female Hu lambs. For 4-month-old female Hu lambs, the recommended fattening energy level is 10.41 MJ/kg.

Effects of dietary energy level on growth performance, blood parameters and meat quality in fattening male Hu lambs.

This experiment was conducted to investigate the effects of different dietary energy levels on growth performance, slaughter traits, meat quality and blood biochemical parameters in fattening male Hu lambs. Sixty lambs were fed five iso-protein diets which contained different levels of metabolizable energy in a completely randomized design for 70 days. At the end of study, fifteen lambs were harvested for further study. With the increase in dietary energy level, the daily weight gain and dry matter intake extremely increased (p < .001), and feed conversion ratio decreased significantly (p < .01). The live weight before slaughter (LWBS) and carcass weight had a significant increase (p < .05), non-carcass fat ratio and routine indexes of meat quality had no significant difference. Almost no effect was observed for the amino acid profile except for glycine concentration decreased (p < .05) in longissimus dorsi (LD) muscle. The concentrations of C17:0, C18:3n-3 and n-3 PUFA (p < .01) significantly decreased with the increasing dietary energy levels, and the ratio of ∑n-6/∑n-3 (p < .01) increased, whereas the concentrations of C18:1n-9t (p < .05) decreased in LD muscle and C18:1 (p < .01) increased in biceps femoris (BF) muscle. There were no obviously differences for diameter, area and density of muscle fibres. The relative expression of MyHC-IIa and MyHC-IIx decreased significantly (p < .05) in BF muscle, and the relative expression of MyHC-IIa displayed an obviously decreasing trend (p < .10) in LD muscle. These results suggest that increasing the dietary energy level can improve the growth performance and slaughter traits, and influence meat quality and fatty acid profiles in different muscle tissues of fattening male Hu lambs. These results provide a theoretical basis for developing Hu sheep nutritional standards and designing feed formulations.