Effects of Dietary Ampitheoe sp. Powder on Growth and Lipid Contents of Litopenaeus vannamei北大核心CSCD

This experiment was conducted to investigate the effects of dietary Ampitheoe sp. powder on the growth and the contents of astaxanthin, triglyceride (TG), total cholesterol (TCHO) and fatty acids of Litopenaeus vannamei. A total of approximately 6 777 L. vannamei with an initial body weight of (1. 80 ± 0.72) g were randomly divided into 3 groups, and there were 3 replicates (753 shrimp per replicate) in each group. Those shrimp fed diets containing 0 (D0 group), 8. 25% (D8. 25 group) and 33% (D33. 00 group) Ampitheoe sp. powder, respectively. The feeding trial lasted for 40 days. The results showed as follows: 1) the final body weight, weight gain rate, specific growth rate, yield and survival rate in D33.00 group were significantly higher than those in D0 group (P <0.05), whereas the feed conversion ratio was significantly lower than that in D0 group (P <0.05) . However, there was no significant difference between D33.00 group and the D8. 25 group in those indexes (P >0.05) . 2) The astaxanthin content in carapace, hepatopancreas and muscle of L. vannamei in D8.25 and D33. 00 groups was significantly higher than that in D0 group (P < 0. 05); that in D33.00 group was significantly higher than that in D8. 25 group (P < 0. 05) . 3) TG content in haemolymph, hepatopancreas and muscle in D8. 25 and D33. 00 groups was significantly lower than that in D0 group (P < 0.05); the TCHO content in hepatopancreas in D8. 25 group was significantly higher than that in D0 and D33.00 groups (P <0.05); TCHO content in muscle in D33.00 group was significantly higher than that in D0 group (P <0.05) . 4) The contents of eicosapentaenoic acid (EPA) and arachidonic acid (AA) in hepatopancreas in D33.00 group were significantly higher than those in D0 group (P <0.05) . The EPA content in muscle in D33.00 group was significantly higher than that in D0 group (P < 0. 05) . In conclusion, adding Ampitheoe sp. powder into the diet can improve the growth performance, the contents of astaxanthin, EPA and AA in L. vannamei, and affect the accumulation of TG and TCHO, which can be used as a functional diet in aquaculture. Considering the cost, the supplementation level of 8. 25% Ampitheoe sp. powder is more appropriate. © 2023 Chinese Journal of Pediatric Surgery. All rights reserved.     

The influence of nitrogen and defoliation on production and water‐use efficiency of Lolium multiflorum cv. Midmar

Abstract

The objective of this study was to investigate the influence of different nitrogen fertiliser application levels in combination with different defoliation intervals on the dry matter (DM) production and water‐use efficiency of ryegrass (Lolium multiflorum,) cv. Midmar. In a field trial, four nitrogen levels (0, 150, 300 and 450 kg N ha^?1) were combined with five defoliation intervals (every 2, 4, 6 and 8 weeks and twice a season). Soil moisture levels were measured with a neutron hydroprobe and were used to schedule irrigation. The dry matter production, nitrogen‐use efficiency (NUE), plant DM content and water‐use efficiency were influenced (P<0.01) by nitrogen level, defoliation interval, and the interaction between these factors. Total DM production varied from 64 to 20 922 kg DM ha^?1. Dry matter production per unit of applied N decreased with an increase in N level within a defoliation interval. The plant DM content varied from 14.0% to 35.6%. The plant DM content decreased (P<0.05) with increasing N applications, while a lengthening of the defoliation interval resulted in an increase (P<0.05) in the DM content. No difference (P>0.05) was found in total water used when plants received N. Water‐use efficiency varied from 1.2 to 25.8 kg DM ha^?1 mm^?1 water received.     

Serosurvey of pathogens in domestic dogs on the border of No?l Kempff Mercado National Park, Bolivia.

The threat of disease transmission from domestic animals to wildlife has become recognized as an increasing concern within the wildlife community in recent years. Domestic dogs pose a significant risk as reservoirs for infectious diseases, especially for wild canids. As part of a multifaceted ecologic study of maned wolves and other canids in the large, remote No?l Kempff Mercado National Park (NKMNP) in northeastern Bolivia, 40 domestic dogs in two villages and at two smaller settlements bordering the national park were sampled for exposure to canine diseases. High levels of exposure were found to canine distemper virus and canine parvovirus, both of which are known to cause mortality in maned wolves and other carnivores. Moderate to high levels of exposure were found to rabies virus, Ehrlichia canis, and Toxoplasma gondii, as well as significant levels of infection with Dirofilaria immitis. This study reports evidence of exposure to several diseases in the domestic dogs bordering the park. Contact between wild carnivores and dogs has been documented in the sampled villages, therefore dogs likely pose a substantial risk to the carnivores within and near NKMNP. Further measures should be undertaken to decrease the risk of spillover infection from domestic animals into the wild species of this region.     

Short‐term effects of fertilizer and stocking rates on the Bankenveld: 2. Animal production

This article on the short‐term effects of veld fertilization in the Bankenveld, deals with the effects of nitrogenous, phosphatic and potassic fertilization, and stocking rates on beef, mutton and wool production. Increased beef production was obtained by applying nitrogenous (linear to 80 kg N/ha) and phosphatic fertilizer to the veld. Fertilization influenced the production of merino sheep less than that of cattle.

Production per animal decreased and that per unit area increased (to a certain point) as a result of increased stocking rates. The expression of these results as MLU/ha or as ha/MLU influenced the form of the response obtained.

Problems were encountered in utilizing fertilized veld, which influenced the economics of the practice. In spite of poor utilization, on some treatments, it appears that veld fertilization can be profitable in its initial stages.     

Effect of dexmedetomidine vs. acepromazine–methadone premedication on limb to lung circulation time in dogs

The study compared limb-to-lung circulation times (CT) in dogs under general anaesthesia after premedication with dexmedetomidine (DEX) or acepromazine–methadone (ACE–M). Healthy male and female dogs (n = 20) were randomly assigned to receive acepromazine 0.04 mg/kg and methadone 0.2 mg/kg intramuscularly (IM), or DEX 0.01 mg/kg IM. Anesthesia was induced with propofol and maintained with isoflurane at similar concentration in both groups. Mechanical ventilation was started immediately (20 breaths/min; inspiratory to expiratory ratio 1:2) and tidal volume was adjusted to achieve an end-tidal CO₂ concentration (PE’CO₂) of between 3.9 and 5.3 kPa. Ten minutes later arterial blood gas was analyzed and baseline data recorded for 3 minutes. A single dose of sodium bicarbonate 0,5 mEq/kg was administered intravenously over 10 s starting with inspiration. Limb-to-lung CT was defined as the time interval between the start of bicarbonate injection and the recording of the highest PE’CO₂.Following bicarbonate administration, PE’CO2 increased, and then rapidly decreased to baseline in both groups. CT was shorter in the ACE–M group (20 ± 2.3 vs. 27 ± 5.1 s). Bodyweight was higher in the ACE–M group (30.6 ± 3.9 vs. 23.3 ± 6.8 kg). Mean arterial blood pressure was higher in the DEX group (92 ± 9 vs. 73 ± 7 mm Hg) but premedication with DEX significantly prolonged CT compared to premedication with ACE–M.     

Beneficial Effects of Rhodotorula sp. C11 on Growth and Disease Resistance of Juvenile Japanese Spiky Sea Cucumber Apostichopus japonicus

The purpose of this study was to evaluate the effects of dietary administration of the live yeast, Rhodotorula sp. C11, on growth and disease resistance against Vibrio splendidus infection in juvenile Japanese spiky sea cucumber Apostichopus japonicus. Sea cucumbers were fed diets containing Rhodotorula sp. C11 at 0 (control), 10⁴, 10⁵, and 10⁶ CFU/g of feed for 45 d. There were three replicate tanks per dietary treatment. The specific growth rates were higher in all sea cucumbers treated with Rhodotorula sp. C11 than in the controls. Following a challenge with V. splendidus NB13, the cumulative prevalence and mortality of sea cucumbers fed diets supplemented with Rhodotorula sp. C11 were lower than in animals fed the basal diet. In sea cucumbers fed diets supplemented with Rhodotorula sp. C11 for 42 d, the only viable yeast found in the intestine was Rhodotorula sp. C11, which had counts of 1.58–1.98 × 10⁴ CFU/g. No yeast was isolated from the intestine of animals fed the basal diet. For the colonization study, 20 sea cucumbers from each dietary treatment were removed to separate tanks and fed the control diet from day 16 to day 46. The viable yeast (Rhodotorula sp. C11) counts in the intestine decreased to 60–80 CFU/g by day 37. Moreover, as demonstrated by denaturing gradient gel electrophoresis, Rhodotorula sp. C11 colonization of the intestine could be detected until day 46. The differences in culture and PCR-denaturing gradient gel electrophoresis may be due to differences in the sensitivity of both methods. The present result showed that Rhodotorula sp. C11 was able to successfully colonize the intestine of juvenile Japanese spiky sea cucumbers by dietary supplementation, which improved its growth and disease resistance.

Received August 11, 2014; accepted November 14, 2014     

Study on The Isozyme of Wild Yak

We have adopted PAGE method to isolate lactic dehydrogenase(LDH)and α-amylase(α-Am)from wild yak's serum and measure the physical-chemical properties of the two components respectively. The results showed that the yak LDH isozyme distributed into five bands. The sequence according to their activity reads as LDH1 ＞ LDH2＞ LDH3 ＞ LDH4 ＞ LDH5. The subunit B is relatively occupied a dominant position. It got a wide operating pH range, high thermal stability,well denature resistance and a fairly large adaptability threshold on the physical-chemical change of surrounding environment. α-Am isozyme distributed into seven bands and also got a wide operating pH range. α-Am isozyme is high sensitivity to environmental temperature.     

Effect of post‐mortem temperature on chicken M. pectoralis major: Isometric tension and pH profiles

1. The relationship between isometric tension development and pH, as a function of storage temperature between 0° and 40°C, was examined in chicken M. pectoralis major (PM) muscle during the critical 24 h post‐mortem period.

2. The muscle strips incubated at 0°C developed a peak isometric tension of 53.3 g/cm². This occurred after only 17 min incubation when the pH was 7.02, demonstrating the potential of chicken PM muscle to cold shorten. Peak isometric tension at 5°C was considerably lower than that generated at 0°C. However, as this occurred when the muscle pH was still high (6.70), this also indicated some potential to cold shorten at 5°C.

3. At 10° to 30°C, the muscle strips developed mean peak isometric tensions of 18 g/cm² after 6 h incubation by which time the muscle pH had fallen to 6.00, demonstrating a limited potential to rigor shorten. In contrast, those incubated at 40°C developed a peak tension of 54.5 g cm² after 75 min when the muscle pH was also around 6.00, thus indicating the potential for intensive rigor shortening at this temperature. Incubation temperature and the resultant muscle pH therefore determine the potential of chicken PM muscle to either cold shorten or rigor shorten.

4. Despite the differences found in isometric tension profiles, cooked meat texture after isometric tension measurement was not significantly different at any of the temperatures studied primarily because the muscle strips were essentially prevented from shortening.     

Absence of effects of dietary α‐tocopherol on egg yolk pigmentation

1. Three experiments were carried out in which yolk colour and carotenoid content were measured in hens fed diets containing soyabean oil or tallow and supplemented with 0, 10, 20, 40, 80, 160 or 320 mg tocopheryl acetate.

2. Fat type had no consistent effect on yolk carotenoid content but yolk α‐tocopherol concentrations were lower with the soyabean oil diet.

3. Yolk concentrations of all carotenoids measured and yolk colour were unaffected by dietary α‐tocopherol concentration.     

Effect of post‐mortem temperature on chicken M. pectoralis major: Muscle shortening and cooked meat tenderness

1. Muscle shortening, sarcomere lengths and pH values were measured in strips of chicken M. pectoralis major (PM) muscle incubated at different time (0 to 24 h) and temperature (0° to 40°C) combinations immediately after slaughter; their effects on cooking loss and meat tenderness determined.

2. Maximum muscle shortening of 39% and 43% occurred at 0°C and 40°C respectively. At 0°C, most shortening occurred within 90 min postmortem when the pH of the muscle ranged from 7.13 to 6.52. In contrast, at 40°C, most shortening occurred during the development of rigor mortis, between 90 and 380 min post‐mortem, when the muscle pH ranged from 6.16 to 5.89. In a similar manner, minimum sarcomere lengths of 1.38 μm were reached after 90 min at 0°C while more severe sarcomere shortening, to 0.96 μm and 0.86 μm at 30°C and 40°C respectively, was not complete until after 380 min post‐mortem. Between 5°C and 20°C, muscle shortening ranged from 25 to 34% while minimum sarcomere lengths of 1.33 μm were recorded.

3. Cooking losses increased on average from 7 to 16% between 30 and 380 min post‐mortem, with maximum losses of 19% being achieved by the end of the 24‐h incubation period.

4. At 0°C, shear force values increased from 2.94 kg/cm² to 4.34 kg/cm² between 30 and 90 min post‐mortem while the muscle pH was > 6.5. At all other temperatures, increases in shear force values were not detected until 380 min post‐mortem when the muscle pH had fallen to 5.9 and rigor mortis had set in. At all times after 380 min, however, the muscle strips incubated at 0, 5 and 40°C had lower shear values (range 3.17 to 5.49 kg/cm²) than those incubated from 10°C to 30°C (range 5.06 to 7.22 kg/cm²).

5. A significant quadratic relationship was found between the degree of shortening and subsequent cooked meat tenderness, in which peak toughness occurred at 30% shortening. This would suggest that the actual extent of muscle shortening per se has an important role to play in determining the tenderness of chicken post‐mortem. Consequently, with unrestrained chicken muscle, where extensive shortening occurred at 0°C and 40°C (i.e cold‐ and rigor shortening) the cooked meat was more tender than that subjected to intermediate post‐mortem temperature regimens.     

The effect of a homologous bacterin given to sows prefarrowing on the development of Glässer's disease in postweaning pigs after i.v. challenge with Haemophilus parasuis serotype 5

The trial was carried out to evaluate the impact of maternal antibodies on the development of Gl?sser's disease after i.v. exposure of weaned pigs with a homologous serovar of Haemophilus parasuis (HPS). Two groups of weaned pigs were formed. Group one VI (n = 10): born to vaccinated sows, weaners i.v. challenged one week postweaning and euthanatized 14 days postweaning. Group two NVI (n = 10 wearners): born to non vaccinated sows, i.v. challenged one week postweaning euthanatized 14 days postweaning. One week postweaning all weaners were i.v. inoculated with HPS serovar 5. The following parameters were evaluated: clinical signs (depression, centralnervous signs, fever, lameness), macroscopic lung, pleura, peritoneum, liver and joint changes, and mortality. All trial sows were HPS seronegative prior to vaccination. The HPS vaccinated sows were proven seropositive on day 3 p.p. (values > 0.24), the non vaccinated ones were tested seronegative (values < 0.23). The progeny of sows vaccinated prefarrowing with two doses of HPS serovar 5 bacterin were partially protected against HPS caused clinical and pathological signs. The majority of clinical signs as fever, depression, recumbency, lack of response to verbal stimuli and lameness showed significant (P < 0.05) milder clinical symptoms in VI than in NVI animals. Respiratory signs (P = .169) and involvement of the central nervous system as ataxia, muscular tremor, incoordination of hind legs and convulsions (P = 1) showed no significant differences between the groups. Except lesions of pericard (VI vs. NVI, P = .14) and pleura (VI vs. NVI, P = .14) there were significant (P < 0.05) macroscopic differences at necropsy in lung, liver, joints and cerebrospinal fluid between the offspring of vaccinated sows and the ones of non vaccinated dams. No HPS were isolated from the nasal mucosa of the pigs prior to inoculation. HPS serovar 5 was recovered at necropsy from the nasal mucosa of all pigs in both groups. One pig from group VI presented in all examined organs the presence of HPS serovar 5. The remaining animals in group VI revealed in lung, pericard, pleura, liver, joints and cerebrospinal fluid no presence of HPS. The rate of isolation between VI and NVI groups revealed a significant (P < 0.05) difference. All the survived piglets of group NVI showed positive ELISA titres against HPS serovar 5 (values > .24). The piglets that died or were euthanatized before the end of the study have not been subjected to ELISA serological testing. One piglet died in group VI before the end of the study. Non of the remaining animals in group VI showed seroconversion to HPS serovar 5. Implications: Vaccination of sows did not influence the colonisation of nasal mucosa, but progeny of sows vaccinated prefarrowing with two doses of HPS serovar 5 bacterin were partially protected against HPS caused diseases.