Determination of N-Carbamylglutamate in Feeds and Animal Products by High Performance Liquid Chromatography Tandem Mass Spectrometry

Study on the correlation of supplementation with L-citrulline on the gastrointestinal flora and semen antifreeze performance of ram

Introduction

Cryopreservation of semen can give full play to the reproductive advantages of male animals. However, in actual production, due to the poor frost resistance of sheep semen and the low conception rate, the promotion of sheep frozen semen is greatly hindered. Therefore, it is urgent to improve the frost resistance of semen to improve the quality of frozen semen. At present, most studies on improving the quality of frozen semen are based on the improvement of semen dilutions, and few studies on improving the freezing resistance of ram semen by feeding functional amino acids.

Methods

Therefore, 24 Turpan black rams were divided into high antifreeze group (HF) and a low antifreeze group (LF) Each of these groups was further randomly divided into control and experimental subgroups. The control subgroup was fed a basal diet, while the experimental subgroup received an additional 12 g/d of L-Cit supplementation based on the control group for a duration of 90 days.

Results

The results showed that Following L-Cit supplementation, the experimental group demonstrated significantly elevated sperm density and VSL (Velocity of straight line), T-AOC, GSH-Px, and NO levels in fresh semen compared to the control group (P < 0.01). After thawing, the experimental group exhibited significantly higher levels of T-AOC, GSH-Px, and NO compared to the control group (P < 0.01). Additionally, the HFT group, after thawing frozen semen, displayed significantly higher HK1 protein expression compared to the control group. The number of spermatogonia, spermatocytes, and sperm cells in the HFT group was significantly higher than that in the HFC group. Moreover, 16S rRNA sequence analysis showed that Candidatus_Saccharimonas, Staphylococcus, Weissella, succinivbrionaceae_UcG_002, and Quinella were significantly enriched in the rumen of the HFT group, while Ureaplasma was significantly enriched in the HFC group. In the duodenum, Clostridiales_bacterium_Firm_14, Butyrivibrio, and Prevotellaceae_NK3831_group were significantly enriched in the HFT group, whereas Desulfovibrio and Quinella were significantly enriched in the HFC group.

Discussion

Under the conditions employed in this study, L-Cit supplementation was found to enhance the intestinal flora composition in rams, thereby improving semen quality, enhancing the antifreeze performance of semen, and promoting the development of testicular spermatogenic cells.

Effects of dietary N-carbamylglutamate on rumen fermentation parameters, and bacterial community diversity of Holstein dairy cows in Tibet

Introduction

The Tibetan Plateau is characterized by low temperature and hypoxia. N-carbamylglutamic acid (NCG) can increase blood oxygen saturation, and have the potential to be used to prevent the high-altitude hypoxia stress state of cows. However, its beneficial effect on the rumen microbiota of Holstein dairy cows remains unclear.

Methods

Hence, the experiments 12 multiparous (parity ranged from 2 to 7) Holstein dairy cows (413.0 ± 42 kg) were randomly assigned to 2 treatments with 6 replicates in each treatment: basal diet (CON, control group) and basal diet plus 20 g/d/cow of NCG (NCG, experiment group), respectively. To study the effects of dietary NCG supplementation on rumen microbiota of Holstein dairy cows in Tibet. The experiment lasted for 45 days, with 15 days of pre-feeding and 30 days of formal trail period.

Results

The results showed that ruminal NH₃-N concentration in NCG group was lower (p < 0.05) than that in the CON group, while molar proportion of acetic acid and total volatile fatty acid (VFA) concentration were increased (p < 0.05) with the addition of NCG. Microbial diversity increased (p < 0.05) in NCG group, with Bacteroidetes, Firmicutes, and Patescibacteria as the most abundant phyla. The KEGG pathway analysis showed that the potential function of ruminal bacteria was mainly enriched in metabolism (carbohydrates, amino acids, lipids, energy, and nucleotides) and genetic information processing (replication, repair, and translation).

Conclusion

In conclusion, NCG can improve rumen nitrogen utilization, total VFA and acetic acid production, and increase rumen microbial diversity, all of which could make the introduced Holstein dairy cows to better adapt to the harsh environment in Tibet and improve their production performance.

Effect of L-citrulline Supplementation on Sperm Characteristics and Hormonal and Antioxidant Levels in Blood and Seminal Plasma of Rams

With the aim of providing a theoretical basis for the application of L-citrulline (L-Cit) in animal husbandry, the effects of L-Cit on reproductive hormone levels, antioxidant capacity, and semen quality of rams were studied by feeding them varying doses of L-Cit. A total of 32 rams were randomly divided into four groups with eight rams each. After all rams were trained to donate sperm normally, the control group was fed a basic diet, whereas the experimental groups I, II, and III were provided with feed supplemented with 4, 8, and 12 g/d of L-Cit, respectively.The experiment was conducted for 70 days, during which blood samples were collected from the jugular vein on days 0, 15, 30, 45, and 60, and semen samples were collected on days 0, 20, 40, and 60. In the same group, 100 µL of semen was used to test for quality, The rest of the semen sample and blood samples were centrifuged at 3500 rpm for 15 min, and the supernatant and serum, respectively, were used to determine the levels reproductive hormones and antioxidant indices. Ram semen samples were also collected on day 70 and used to study sperm plasma membrane, substitution, and mitochondrial membrane potential. Compared with the control group, the groups receiving L-Cit showed an increase in sperm concentration and number of linear motile sperm (P < 0.01); decrease in the number of dead sperm (P < 0.01); increase in sperm viability, particularly in groups II and III (P < 0.01); and increase in sperm mitochondrial membrane potential (P < 0.01). Moreover, groups I, II, and III showed significantly higher levels of serum gonadotropin-releasing hormone (GnRH), glutathione peroxidase (GSH-Px), and nitric oxide (NO) (P < 0.01). Luteinizing hormone (LH) and follicle-stimulating hormone (FSH) levels increased in groups I (P < 0.05), II (P < 0.05), and III (P < 0.01), whereas testosterone (T), catalase (CAT), and superoxide dismutase (SOD) levels increased in groups I and II (P < 0.01). Serum total antioxidant capacity (T-A) increased (P < 0.05), whereas both hydroxyl radical (·OH) and peroxy radical (O2·-) levels decreased (P < 0.01). Compared with the control, all groups had significantly higher SOD and GSH-Px in their seminal plasma (P < 0.01), and groups I, II (P < 0.05 for both), and III (P < 0.01) had higher levels of GnRH and FSH. LH, CAT, and NO levels increased in group I (P < 0.05), II, and III (P < 0.01 for both); malondialdehyde levels decreased in groups I, II (P < 0.05 for both), and group III (P < 0.01); and O2·- levels decreased in groups I, II, and III (P < 0.01). Under our experimental conditions, GnRH, FSH, LH, T, CAT, SOD, T-A, GSH-P_X , and NO levels in the serum and seminal plasma of rams receiving L-Cit increased, whereas Estradiol(E₂ ), O2_· ^- and ·OH levels in the seminal plasma decreased; this improved the semen quality of rams supplemented with L-Cit. Moreover, supplementation with 12 g/d gave the best results.