Relationships between oxidative stress markers and red blood cell characteristics in renal azotemic dogs

Oxidative stress parameters and erythrocyte characteristics were studied in 15 normal healthy dogs and 33 renal azotaemic dogs from Small Animal Hospital, Faculty of Veterinary Science, Chulalongkorn University. Dogs with renal azotaemia had reduced mean corpuscular volume (MCV) (P < 0.01), packed cell volume (PCV) (P < 0.001) and increased mean corpuscular hemoglobin concentration (MCHC) (P < 0.001). The relationship was found between degree of azotaemia and MCV, PCV and MCHC. Dogs with severe renal azotaemia had higher intraerythrocytic sodium contents (RBC-Na) (P < 0.05). The red blood cell catalase activity and glutathione and plasma malondialdehyde were unaltered while urinary malondialdehyde-creatinine ratio (U-MDA/Cr) increased significantly (P < 0.001). The U-MDA/Cr was correlated significantly with plasma creatinine concentration (P < 0.05), urinary protein-creatinine ratio (P < 0.05) and fractional excretion of sodium (P < 0.001). The results suggest some changes in RBC characteristics and urine oxidative stress marker in renal azotaemic dogs. Moreover, the U-MDA/Cr is a sensitive biochemical parameter which increased along with degree of renal dysfunction.     

Corpuscular oxidation in newborn crossbred calves naturally infected with Theileria annulata

Erythrocytic lipid peroxidation has been implicated as a cause of anemia in Theileria annulata infection in cattle. The present study aimed to evaluate oxidative damage of membrane lipids and proteins in addition to hemoglobin (Hb) as three criterions of erythrocyte oxidation and their relation to erythrocyte deformability and anemia of newborn crossbred calves (Friesian × Egyptian Balady breed) naturally infected with T. annulata. Twenty-five T. annulata-infected calves (aged 20-30 days) along with 15 age matched healthy controls were used. Percentage of parasitemia varied from 12% to 63% (34.76 ± 3.05%). In comparison to controls, infected calves showed increased levels (P<0.001) of lipid peroxidation (malondialdehyde; MDA, 52%) and protein oxidation (protein carbonyls; PCs, 132%) in erythrocyte membrane as well as increased values of Hb oxidation (methemoglobin; MetHb, 186%), corpuscular osmotic fragility (15.1%) and hemolysis (free Hb; 195.5%). Parasitemia was positively correlated with MDA (r=0.41, P=0.039), PCs (r=0.45, P=0.023) and MetHb (r=0.40, P=0.042). Also, percent of erythrocytic deformability (echinocytosis) was positively correlated with MDA (r=0.49, P=0.013) and PCs (r=0.63, P<0.001). On the other hand, erythrocytic packed cell volume was negatively correlated with MDA (r=-0.44, P=0.028), PCs (r=-0.72, P<0.001) and MetHb (r=-0.42, P=0.037). In conclusion, T. annulata infection is associated with a parasitic burden-dependant oxidative damage to the erythrocyte membrane protein and lipid contents in addition to Hb. This oxidative damage is linked to the morphological changes of the erythrocyte and may act as mechanisms contribute to pathogenesis of anemia in T. annulata infection in newborn calves.     

Evaluation of the in vitro growth-inhibitory effect of epoxomicin on Babesia parasites

Epoxomicin potently and irreversibly inhibits the catalytic activity of proteasomal subunits. Treatment of proliferating cells with epoxomicin results in cell death through accumulation of ubiquinated proteins. Thus, epoxomicin has been proposed as a potential anti-cancer drug. In the present study, the inhibitory effects of epoxomicin on the in vitro growth of bovine and equine Babesia parasites were evaluated. The inhibitory effect of epoxomicin on the in vivo growth of Babesia microti was also assessed. The in vitro growth of five Babesia species that were tested was significantly inhibited (P < 0.05) by nanomolar concentrations of epoxomicin (IC₅₀ values = 21.4 ± 0.2, 4 ± 0.1, 39.5 ± 0.1, 9.7 ± 0.3, and 21.1 ± 0.1 nM for Babesia bovis, Babesia bigemina, Babesia ovata, Babesia caballi, and Babesia equi, respectively). Epoxomicin IC₅₀ values for Babesia parasites were low when compared with diminazene aceturate and tetracycline hydrochloride. Combinations of epoxomicin with diminazene aceturate synergistically potentiated its inhibitory effects in vitro on B. bovis, B. bigemina, and B. caballi. In B. microti-infected mice, epoxomicin caused significant (P < 0.05) inhibition of the growth of B. microti at the non-toxic doses of 0.05 and 0.5 mg/kg BW relative to control groups. Therefore, epoxomicin might be used for treatment of babesiosis.     

Occurrence and severity of lung lesions in slaughter pigs vaccinated against Mycoplasma hyopneumoniae with different strategies

Different vaccination strategies against Mycoplasma hyopneumoniae have been adopted worldwide. Reports from the field indicate varying levels of protection among currently available vaccines. The goal of the present study was to compare the efficacies of three widespread commercial vaccination strategies against M. hyopneumoniae under field conditions. 20 farms were included. 14 farms used different single dose vaccines (vaccine 1 [V1], 8 herds; vaccine 2 [V2], 6 herds); another 6 farms (V3) used a two dose vaccination strategy. Gross lesions of 854 lungs and histopathology from 140 lungs were quantified, and a quantitative PCR was applied to detect M. hyopneumoniae and porcine circovirus 2 (PCV2) DNA in lung tissue (n = 140). In addition, porcine reproductive and respiratory disease virus (PRRSV), swine influenza virus (SIV), Actinobacillus pleuropneumoniae, Haemophilus parasuis and Pasteurella multocida were tested by qualitative PCR. 53% of lungs were positive for M. hyopneumoniae. 55.9% of lungs showed macroscopic enzootic pneumonia (EP)-like lesions. Lung lesion scores (P < 0.001) and M. hyopneumoniae-loads (P < 0.008) differed significantly among the vaccination groups, with the most severe cases and highest amounts occurring in V1. Histological alterations differed (P < 0.001) between V1 and V3. Lung lesion scores and histopathological changes were significantly correlated, with prevalence and load of M. hyopneumoniae indicating that the applied diagnostic tools are valuable in confirming the prevalence and severity of M. hyopneumoniae infections. Comparing different vaccination strategies against M. hyopneumoniae indicates varying levels of protection. M. hyopneumoniae is still a major problem despite the widely applied vaccination.     

Circulating oxidative stress status in dromedary camels infested with sarcoptic mange

Oxidative stress is an imbalance between radical-generating and radical-scavenging activity, resulting in oxidation products and tissue damage. This study was aimed to evaluate the status of oxidative stress indices in blood of camels naturally infested with S. scabiei. Forty-seven male camels (Camelus dromedaries) were divided according to the extent of the infested area with Sarcoptes scabiei into four groups, mild (MID, n = 12), moderate (MOD, n = 10), severely infested (SEV, n = 10) and healthy control group (n = 15). Blood was used for determination of red cell count (RBC), hemoglobin (Hb), packed cell volume (PCV), serum nitric oxide (NO^•, a free radical), ascorbate and albumin concentrations, and erythrocytic values of malondialdehyde (MDA, a marker of lipid peroxidation), protein carbonyls (PC, an indicator of protein oxidation), glutathione (GSH) superoxide dismutase (SOD) and catalase (CAT). Decreased levels (P < 0.05) of RBC, Hb, PCV, albumin and ascorbate were noticed in MOD and SEV compared to controls with the lowest values (P < 0.05) in SEV except for ascorbate, where MOD did not differ from SEV. Compared to controls, NO^• gradually increased (P < 0.05) in MID followed by MOD and SEV, whereas MDA and PC were higher (P < 0.05) in MOD and SEV. PC was higher (P < 0.05) in MOD than SEV. In addition, the antioxidants GSH, SOD and CAT were higher (P < 0.05) in MID and lower (P < 0.05) in MOD and SEV compared to controls. GSH was lower (P < 0.05) in SEV compared to MOD. Besides, Hb was negatively correlated with NO^• (r = −0.68, P < 0.001), MDA (r = −0.53, P < 0.001) and PC (r = −0.73, P < 0.001). In conclusion, dromedary sarcoptosis is accompanied by a state of oxidative stress process, which increased by increasing the area of infestation, and may contribute to the pathogenesis of the disease.     

Assessment of the effects of different concentrations of ethylenediaminetetraacetic acid (EDTA) on erythrocytic indices of Nigerian White Fulani cattle and West African Dwarf goat

The aim of the study was to evaluate the effects of varying concentrations of ethylenediaminetetraacetic acid (EDTA) on blood samples from White Fulani breed of cattle and West African Dwarf goat from Nigeria. Sample sizes of 20 animals were used for both species. Different concentrations of EDTA (2, 4, 8 and 16 mg/ml) were used. The packed cell volume (PCV), red blood cell (RBC) and haemoglobin (Hb) concentration of blood samples collected from White Fulani breed of cattle and West African Dwarf goat into bottles containing 16 mg/ml of EDTA were significantly lower (P < 0.05) than those samples collected from the same animals into bottle containing 2 mg/ml (control). Similarly, the PCV, RBC and Hb values of the West African Dwarf goats in bottles containing 8 mg/ml of EDTA were significantly lower than those of the samples in the control (2 mg/ml). This study has shown that high concentration of EDTA as an anticoagulant can lead to a false erythrocytic index especially the PCV. In collecting blood samples for evaluation of haematological parameters, therefore, the blood volume/anticoagulant ratio must be strictly adhered to prevent error in the evaluated parameters in cattle and goats. Taken together, there is tendency for haemolytic anaemia to occur in blood sampled at higher concentration of anticoagulants in West African Dwarf goat than in White Fulani breed of cattle.     

Intravaginal administration of lactic acid bacteria modulated the incidence of purulent vaginal discharges,plasma haptoglobin concentrations,and milk production in dairy cows

This investigation studied the effects of intravaginal administration of a mixture of lactic acid bacteria (LAB) on the incidence of purulent vaginal discharges (PVD), plasma haptoglobin concentrations, and milk production in dairy cows. A total of 82 pregnant primiparous and multiparous Holstein dairy cows were used in this study. Half of the cows received intravaginally 1 mL of LAB at 10¹⁰–10¹² cfu/mL and the other half 1 mL of reconstituted skim milk (i.e., carrier) (controls). Administration of LAB was conducted once per wk during 2 and 1 wk before the expected day of calving and at 1, 2, 3, and 4 wk postpartum. Data demonstrated that intravaginal administration of LAB decreased the occurrence of PVD at 3 wk postpartum (P < 0.05). Concentrations of plasma haptoglobin, an acute phase protein often associated with uterine infections, was lower in cows treated with the LAB mixture at 2 wk (P < 0.001) and 3 wk (P < 0.05) postpartum. Treatment with LAB did not improve overall pregnancy rate, but the treated multiparous cows produced more milk than their control counterparts (P < 0.05), whereas no difference was observed in primiparous cows regarding milk yield (P > 0.05). Overall, this is the first study demonstrating that intravaginal LAB administration lowers the incidence of PVD and enhances milk production in dairy cows. Further research is warranted to evaluate the effects of LAB on reproductive performance in a larger cohort of cows.     

Effect of daidzein on production performance and serum antioxidative function in late lactation cows under heat stress

Forty Chinese Holstein cows were randomly divided into 4 groups according to birth, milk yield, and close lactation. The cows in 4 groups were fed with basic diet, basic diet plus 200, 300, 400 mg/day daidzein, respectively; and the experimental period was 60 days. The milk yield in all cows was monitored everyday and the quality of milk was examined regularly. Blood was collected on days 0, 10, 30, 60 of experiment to isolate serum, and the activities of superoxide dismutase (SOD), glutathione peroxidase (GSH-Px) and catalase (CAT), malondialdehyde (MDA) content, and total antioxidant capacity (TAC) in the serum were measured. Results showed that the milk yield and the percentage of milk fat were significantly higher after feeding daidzein (P<0.01), and the percentage of milk protein was significantly elevated on day 60 in three daidzein groups (P<0.05 or P<0.01), especially in 400 mg/day daidzein group (P<0.01). Compared with the control group (basic diet), the TAC and activities of SOD, GSH-Px and CAT were markedly elevated in three daidzein groups (P<0.05 or P<0.01), while the MDA content was significantly reduced in three daidzein groups (P<0.05 or P<0.01). All data suggest that daidzein has positive effects on increasing the production performance and antioxidative activity in late lactation cows, and enhancing the body adaptability and resistance to heat stress.     

Dietary grain source and oil supplement: Feeding behavior and lactational performance of Holstein cows

Effects of grain source and dietary oil supplement on dry matter intake (DMI), feeding, chewing behavior, and production performance of lactating dairy cows were evaluated using eight multiparous Holstein cows (77±22.1 days in milk; mean±SD) in a duplicated 4×4 Latin square design with a 2×2 factorial arrangement of treatments. Experimental diets contained either ground barley or ground corn supplemented with either fish oil or soybean oil at 2% of dietary dry matter (DM). Geometric mean particle size of dietary treatments was 4.1 mm. Dry matter intake tended (P=0.09) to be greater for barley- vs. corn-based diets (23.2 vs. 22.3 kg/d), but was reduced for the fish oil compared to soybean oil supplemented diets (21.1 vs. 24.3 kg/d; P<0.001). This reduction in DMI was attributed to smaller meal size (1.24 vs. 1.55 kg of DM; P=0.004) and slower eating rate (0.082 vs. 0.098 kg of DM/min; P<0.001) for fish oil compared to soybean oil supplemented diets. Main treatment effects interacted (P=0.005) for DMI of particles retained on 19 mm sieve but not for sorting index. Eating rate (0.090 kg of DM/min) was similar between barley- and corn-based diets, however, rumination time was greater for barley- compared to corn-based diets as result of longer rumination bout duration (32.5 vs. 28.5 min/bout; P=0.01). Barley- compared to corn-based diets increased total chewing time by 71 min (709 vs. 638 min) for cows fed fish oil, but not for cows fed soybean oil. Grain source did not affect milk yield or milk composition. Compared to soybean oil, fish oil negatively affected milk yield (40.4 vs. 43.4 kg/d; P=0.01), and thereby, both milk fat (0.91 vs. 1.26 kg/d; P<0.001) and protein (1.23 vs. 1.33 kg/d; P=0.007) production. However, feed efficiency (milk yield/DMI) was greater in fish oil compared to soybean oil supplemented diets (1.94 vs. 1.80; P=0.003). Results indicated that grain source and oil supplement can interact to affect feeding and chewing behavior, but not lactational performance of lactating cows.     

Comparison of the performance of Holstein-Friesian and Jersey×Holstein-Friesian crossbred dairy cows within three contrasting grassland-based systems of milk production

The performance of spring calving Holstein-Friesian (HF) and Jersey×Holstein-Friesian (J×HF) dairy cows was examined during three successive years (mean of 35 HF cows and 31 J×HF cows per year). Throughout the experiment cows were managed on one of three grassland-based systems of milk production, namely low concentrate (LC), medium concentrate (MC) or high concentrate (HC). Post-calving, cows were housed and offered grass silage, supplemented with 6.0, 8.0 and 10.0 kg concentrate/cow/d in systems LC, MC and HC, respectively (mean period from calving to start of full time grazing, 69 days). During the grazing period target concentrate feed levels were 0, 2.5 and 5.0 kg/cow/d for systems LC, MC and HC, respectively (mean period from start of full time grazing to start full time re-housing, 206 days). Full lactation concentrate inputs were 530, 1092 and 1667 kg/cow, in systems LC, MC and HC, respectively. There were no significant genotype×system interactions for any of the milk production parameters examined. Food intake during the confinement and grazing periods was unaffected by genotype. Milk yield was highest with HF cows while milk fat and milk protein content were highest with the J×HF cows (P<0.001). Genotype had no effect on fat plus protein yield. Milk yield and fat plus protein yield were higher with systems MC and HC than with LC (P<0.001). HF cows were on average 44 kg heavier than J×HF cows, while the mean condition score of the J×HF cows was approximately 0.2 units higher than that of the HF cows (P<0.001). Live weight and condition score changes during the lactation followed similar trends with both genotypes. The J×HF cows had fewer days to first observed heat (P<0.05), a higher conception rate to first service (P<0.01), first plus second service (P<0.001), and a higher pregnancy rate at the end of the breeding season (P<0.05). Although mean somatic cell score was unaffected by genotype, the proportion of cows with one or more cases of mastitis was lower with the J×HF cows (P<0.05). In summary, while the J×HF cows had improved fertility performance compared to the HF cows, both genotypes exhibited similar levels of tissue mobilisation and deposition throughout the lactation, while there was no evidence of a genotype×grassland system interaction for any of the milk production parameters examined.     

Bartonella and Babesia infections in cattle and their ticks in Taiwan

Bartonella and Babesia infections and the association with cattle breed and age as well as tick species infesting selected cattle herds in Taiwan were investigated. Blood samples were collected from 518 dairy cows and 59 beef cattle on 14 farms and 415 ticks were collected from these animals or in a field. Bartonella and Babesia species were isolated and/or detected in the cattle blood samples and from a selected subset (n = 254) of the ticks either by culture or DNA extraction, PCR testing and DNA sequence analysis. Bartonella bovis was isolated from a dairy cow and was detected in 25 (42.4%) beef cattle and 40 (15.7%) tick DNA samples. This is the first isolation of B. bovis from cattle in Asia and detection of a wide variety of Bartonella species in Rhipicephalus microplus. Babesia spp. were detected only on one farm from dairy cows either infected by Babesia bovis (n = 10, 1.9%) or B. bigemina (n = 3, 0.6%).     

Comparative clinico-haematological analysis in young Zebu cattle experimentally infected with Trypanosoma vivax isolates from tsetse infested and non-tsetse infested areas of Northwest Ethiopia

Background

Ethiopia, particularly in the Northwest region, is affected by both tsetse and non-tsetse fly transmitted trypanosomosis, with significant impact on livestock productivity. The aim of this study was to determine and compare clinical findings and haematological values between experimental infections induced by Trypanosoma vivax isolates from areas of either transmission mode. Sixteen young (aged between 6 and 12 months) Zebu cattle (Bos indicus), purchased from a trypanosome-free area and confirmed to be trypanosome-negative, were randomly assigned into four groups of four animals. Groups 1, 2 and 3 were infected with an isolate from a tsetse infested or one of two isolates from a non-tsetse infested area, and group 4 was a non-infected control. All animals in the infected groups were inoculated intravenously with 2 × 10⁶ trypanosomes from donor animals. The experimental animals were monitored for eight consecutive weeks post infection for clinical signs, parasitaemia and haematological changes in packed cell volume (PCV), haemoglobin concentration (Hgb), total red blood cell (RBC) and white blood cell (WBC) counts, differential WBC count and blood indices (mean corpuscular volume [MCV], mean corpuscular haemoglobin and mean corpuscular haemoglobin concentration).

Results

Infection was characterized by reduced feed intake, weakness, pyrexia, parasitaemia, rough hair coat, enlarged prescapular lymph nodes, lacrimation, weight loss, pallor mucus membrane and dehydration. Body weight loss in all infected groups was significantly higher than in the non-infected control. Similarly, body weight loss was higher (P < 0.001) in animals infected with the tsetse infested isolate than with the non-tsetse infested isolates. The mean PCV, Hgb, total RBC and WBC counts were lower (P < 0.001), and mean MCV was higher (P = 0.01) in all infected groups than in non-infected control animals at different time points during the study period. Except for minor variations in haematological values, the overall changes were similar in all infected groups.

Conclusion

Clinical signs and significant reduction in haematological values in the infected groups indicated the pathogenicity of the T. vivax parasites. Pathogenicity of T. vivax from the non-tsetse infested area can be considered as nearly as important as that of its counterpart derived from the tsetse infested area.     

Partial budgeting assessment of the treatment of pyometra, follicular cysts and ovarian inactivity causing postpartum anoestrus in dairy cattle

A total of 412 multiparous German Holstein cows were screened for postpartum pyometra, follicular cysts and ovarian inactivity to assess economic and productivity losses in relation to pharmaceutical expenditures. Our results show that cows treated for pyometra with prostaglandin f2 alpha (PGF2α) and oxytetracycline had significantly (P < 0.05) greater total and net returns than untreated cows or those treated with PGF2α + cephapirin or PGF2α alone. Milk yields from untreated cows affected by follicular cysts were significantly (P < 0.05) lower than the yields from cows treated with gonadotrophin-releasing hormone (GnRH)− and GnRH + PGF2α. In addition, the use of GnRH to treat cows with ovarian inactivity resulted in significantly (P < 0.05) lower costs and greater total and net return values compared to untreated controls.     

Flavonoid mixture ameliorates increase in erythrocyte osmotic fragility and malondialdehyde concentration induced by Trypanosoma brucei brucei-infection in Wistar rats

The experiment was performed with the aim of investigating the effect of a flavonoid mixture, Daflon® 500 mg (DF) on the erythrocyte fragility and lipoperoxidative changes, induced by Trypanosoma brucei brucei infection in Wistar rats. Fifty adult male rats randomly divided into five groups of 10 animals each were used. Rats in the control group were administered (1 mL/kg) distilled water only, while the other groups were infected with T. brucei brucei and treated with Daflon® 500 mg and/or Diminazene aceturate. At the end of 5 weeks, EDTA-blood samples and serum samples were collected from the rats, and were used to determine erythrocyte osmotic fragility (EOF) and serum malondialdehyde (MDA) concentration respectively. The results showed that EOF and MDA concentration significantly (P < 0.05) increased in the infected untreated group when compared to the treatment groups. Treatment with Daflon® 500 mg and Diminazene aceturate significantly (P < 0.05) reduced trypanosome-induced increases in EOF and lipoperoxidative changes, suggesting possible antioxidant properties of Daflon® 500 mg and its therapeutic value in trypanosomosis.     

Subclinical mastitis causes alterations in nitric oxide, total oxidant and antioxidant capacity in cow milk

The aim of this study was to investigate total antioxidant (TAC), and oxidant capacity (TOC) and nitric oxide (NO) levels in milk of cows with subclinical mastitis. Brown Swiss and Holstein breed cows were screened with California Mastitis Test (CMT) to determine mammary glands with subclinical mastitis. Moreover, somatic cell counts (SCC) were determined electronically in all milk samples. Mammary quarters were classified as healthy (n = 25) or subclinical mastitis (n = 35) based on CMT scores and somatic cell count (SCC: ?200,000/ml or >200,000/ml) in milk. Nitric oxide, TOC and SCC levels were significantly higher (p < 0.001, p < 0.005 and p < 0.001, respectively) in milk from mammary quarters with subclinical mastitis compared to those from healthy mammary quarters. In conclusion, subclinical mastitis results in higher NO concentrations, TOC and SCC, and NO and TOC were positively correlated with SCC. Moreover, alterations in NO levels and TOC in milk could be used as an alternative diagnostic tool to screen for subclinical mastitis.     

Effects of cooldown methods and durations on equine physiological traits following high-intensity exercise

This study was initiated to investigate the physiologic effects of cooldown methods and durations on recovery following high-intensity exercise (3000 m, 10 m/s) of 25 Jeju crossbred horses. Heart rate (HR) was measured and blood samples were collected for glucose, blood lactate concentration, packed cell volume (PCV), total protein (TP), and hemoglobin (Hb) analysis. The cooldown methods employed involved walk rest (WR) or trot rest (TR), and the durations compared were 15, 30, and 60 min. A passive rest group (PR) was used as a control. According to the analysis, HR decreased after a 15 min rest in all groups, showing a faster recovery in the active rest groups, WR and TR, than in the PR group after 30 min (P < 0.05). In the case of glucose, the decrease was faster in the WR15 group then the WR30 group suggesting that active rest is more effective in controlling this parameter (P < 0.05). As for lactate, TR15 showed a 75% decrease which was a significantly positive effect. There were no differences in PCV between the groups. Horses in the PR group showed faster recovery for TP and Hb than those in the active rest groups (P < 0.05), while lactate removal was faster in active rest groups than in the PR group, suggesting that the cooldown process plays an important role in recovery. This study showed that the cooldown method and duration employed after high-intensity exercise of horses makes a difference with regard to their physiologic status. Also, 15 min rest after exercise appears to be the most significant period in terms of duration. In conclusion, active rest was necessary for rapid recovery and a 15 to 30 min cooldown walk or trot was beneficial to the horses in which physical fatigue had accumulated. In particular, the active exercise method of trotting was found to be more effective than walking to remove lactate. In addition, the cooldown duration is expected to be more effective when adjusted according to the individual training state of the horse.     

Lipid status, paraoxonase-1 activity and metabolic parameters in serum of heifers and lactating cows related to oxidative stress

The objective of this study was to investigate serum lipids, metabolic parameters and activity of the anti-oxidative enzyme paraoxonase-1 (PON1). The study was conducted on non-pregnant heifers with optimal health status and on healthy dairy cows in the period of intensive lactation, assuming that the energy and metabolic demands during lactation reduce anti-oxidative protection. Total cholesterol and HDL-cholesterol concentrations were significantly higher (P < 0.05) in lactating cows than in heifers. Bilirubin concentration and γ-glutamyltransferase (GGT) activity were also significantly higher in lactating cows (P < 0.05), indicating increased hepatic efforts of cows to meet energy requirements for lactation. Significantly lower PON1 activity and PON1/HDL ratio in lactating cows compared to heifers (P < 0.05) showed that metabolic efforts during pregnancy, parturition and lactation influence PON1 activity due to oxidative stress. Concurrent increase in total and HDL-cholesterol during lactation indicated that the HDL particle is a major carrier of cholesterol in cows.     

Alfalfa polysaccharides improve the growth performance and antioxidant status of heat-stressed rabbits

The study was conducted to evaluate the antioxidant properties of alfalfa polysaccharides (APS) extracted from alfalfa (Medicago sativa L.) through 1,1-Diphenyl-2-picryl-hydrazyl (DPPH) radical-scavenging assay and the effects of the inclusion (0%, 0.1%, and 0.5%) of APS in the diet on the growth performance and antioxidant status in heat-stressed rabbits. 120 New Zealand male rabbits (average body weight 1123 g, 40 d old) were divided into three groups (40 rabbits per group) and were fed with a basal diet or the basal diet with 1 g or 5 g of APS/kg of diet. Rabbits had free access to diets and water in an environmentally controlled room at 30 ± 1 °C and 55% relative humidity during the entire period (21 d). On days 7, 14 and 21 of the trial, body weight and feed intake were measured and blood samples were collected for assay of antioxidant induces. Liver tissue samples were collected on day 21 for assay of antioxidant induces. Results in vitro showed the scavenging effect of APS on DPPH radicals increased (P < 0.05) in a dose-dependent manner. The APS exerted an inhibitory effect on DPPH radical generation, with 66.3% inhibition at 100 µg/mL and 74.5% inhibition at 250 µg/mL. Results in vivo showed that APS 0.1% supplementation increased (P < 0.05) average daily gain (ADG) and reduced (P < 0.05) feed conversion rate (FCR) in the first week of trial. Compared with the control group, average daily feed intake (ADFI) was significantly (P < 0.01) reduced by APS treatment. From days 8 to 14 of the trial, ADG of the APS 0.5% group was greater (P < 0.05) than that of the control group. Compared with the control group, FCR was significantly (P < 0.05) reduced by APS treatment. From days 15 to 21 of the trial, ADFI of the APS 0.1% group was greater (P < 0.05) than that of the control group. For the overall period, APS 0.5% supplementation had a significantly (P < 0.05) positive effect on ADG. ADFI and FCR were lower (P < 0.05) with APS than without APS. Furthermore, on day 7, the inclusion of APS reduced significantly MDA (P < 0.01). The rabbits fed with APS 0.1% had significantly (P < 0.01) lower cortisol and greater (P < 0.05) T-AOC, SOD, and GSH-Px than the control group. On day 14, addition of APS increased T-AOC (P < 0.01) and reduced MDA (P < 0.05). The APS 0.5% group showed lower (P < 0.05) cortisol and greater (P < 0.05) GSH-Px than the control group. On day 21, the rabbits fed with the APS 0.5% diet had greater (P < 0.05) GSH-Px and T-AOC compared with the control rabbits. In contrast, the opposite was true for cortisol (P < 0.05) and MDA (P < 0.05). On day 21, MDA was lower (P < 0.01) with APS than without APS in the liver tissue. Hepatic GSH-Px activity of rabbits fed with the APS 0.5% diet was greater (P < 0.05) than those of other groups. APS supplementation seemed to have a positive influence on the growth performance and antioxidant status of heat-stressed rabbits.     

Babesia bigemina infection in yak (Poephagus grunniens L.): Molecular detection and characterization

Yaks contribute significantly in the Himalayan high land economy. Specific information on prevalence of babesiosis in yaks is lacking. A fast and reliable PCR assay targeting Babesia bigemina small subunit ribosomal RNA sequence (SS rRNA) was laboratory standardized for molecular detection of B. bigemina in yaks. Restriction digestion of the PCR amplified 675 bp target sequence with Vsp I confirmed the prevalent species of Babesia as B. bigemina. Nucleotide sequencing and phylogenetic analysis of PCR amplified 675 bp SS rRNA sequence revealed a close genetic relationship with other bovine isolates of B. bigemina. A PCR based survey involving 94 blood samples of yak from the National Research Centre on Yak, Dirang, Arunachal Pradesh detected infection in 5.32% of yak blood samples, which was significantly higher in comparison to microscope based detection of infection in 2.13% blood smears. This is the first report on sensitive PCR based detection of B. bigemina infection in yaks and PCR-RFLP and nucleotide sequence analysis based molecular characterization of the B. bigemina isolated from yaks.