Consequences of rearing feeding programme on the performance of rabbit females from 1st to 2nd parturition

To evaluate how rearing programmes could affect resources allocation and reproductive performance of primiparous rabbit females, a total of 118 rabbit females were used to evaluate the effects of five rearing feeding programmes on their performance from 1st to 2nd parturition: CAL, fed ad libitum C diet (11.0 MJ digestible energy (DE), 114 g digestible protein (DP) and 358 g NDF/kg dry matter (DM) until 1st parturition; CR, fed ad libitum with C diet until 12 weeks of age and then C diet restricted (140 g/day) until 1st parturition; F, fed ad libitum with F diet (8.7 MJ DE, 88 g DP and 476 NDF/kg DM) until 1st parturition; FC, fed with F diet ad libitum until 16 weeks of age, and C diet ad libitum until 1st parturition; FCF, fed with F diet ad libitum until 16 weeks of age, then C diet ad libitum until 20 weeks and then F diet ad libitum until 1st parturition. From 1st parturition, C diet was ad libitum offered to all the experimental groups until 2nd parturition. CAL females presented lower feed intake than females of F, FC and FCF groups in the 1^st week of lactation (on av. −16.6%; P<0.05). During 1st lactation, the perirenal fat thickness change in CAL females was not different from 0 (+0.02 mm), while in the other four groups it increased (on av. +0.44 mm; P<0.05). Plasma of females fed with F diet during rearing (F, FC and FCF) had lower non-esterified fatty acids content than those exclusively fed with C diet (–0.088 and –0.072 mmol/l compared to CAL and CR, respectively; P<0.05). FCF litters had higher weight than F litters at day 21 of lactation (+247 g; P<0.05), but FCF litter had significantly lower weight than FC litters at weaning (+170 g; P<0.05). CR females had the shortest average interval between the 1st and 2nd parturition (49 days) and FCF females the longest (+ 9 days compared to CR; P<0.05). At 2nd parturition, liveborn litters of F females were larger and heavier than litters of FCF females (+2.22 kits and +138 g; P<0.05), probably due to the lower mortality at birth of F litters (–16.5 percentage points; P<0.05). In conclusion, rearing females on fibrous diets seems to increase the ability of primiparous rabbit females to obtain resources, especially at the onset of lactation.     

De novo malignant solitary fibrous tumor of the kidney

Background

To study the expression of MK-1 and RegIV and to detect their pathological significances in benign and malignant lesions of gallbladder.

Methods

The expression of MK-1 and RegIV was detected by immunohistochemical method in paraffin-embedded sections of surgical resected specimens from gallbladder adenocarcinoma (n = 108), peritumoral tissues (n = 46), adenomatous polyp (n = 15), and chronic cholecystitis (n = 35).

Results

The positive rate of MK-1 or RegIV expression was significantly higher in gallbladder adenocarcinoma than that in peritumoral tissues (X² _MK-1 = 18.76, P < 0.01; X² _RegIV = 9.92, P < 0.01), denomatous polyp (X² _MK-1 = 9.49, P < 0.01; X² _RegIV = 8.59, P < 0.01) and chronic cholecystitis (X² _MK-1 = 24.11, P < 0.01; X² _RegIV = 19.24, P < 0.01). The positive cases of MK-1 and/or RegIV in the benign lesions showed moderately- or severe-atypical hyperplasia of gallbladder epitheli. The positive rates of MK-1 were significantly higher in the cases of well-differentiated adenocarcinoma, no-metastasis of lymph node, and no-invasiveness of regional tissues than those in the ones of differentiated adenocarcinoma, metastasis of lymph node, and invasiveness of regional tissues in gallbladder adenocarcinoma (P < 0.05 or P < 0.01). On the contrary, the positive rates of RegIV were significantly lower in the cases of well-differentiated adenocarcinoma, no-metastasis of lymph node, and no-invasiveness of regional tissues than those in the ones of differentiated adenocarcinoma, metastasis of lymph node, and invasiveness of regional tissues in gallbladder adenocarcinoma (P < 0.05 or P < 0.01). Univariate Kaplan-Meier analysis showed that decreased expression of MK-1 (P = 0.09) or increased expression of RegIV (P = 0.003) was associated with decreased overall survival. Multivariate Cox regression analysis showed that decreased expression of MK-1 (P = 0.033) and increased expression of RegIV (P = 0.008) was an independent prognostic predictor in gallbladder adenocarcinoma.

Conclusions

The expression of MK-1 and/or RegIV might be closely related to the carcinogenesis, clinical biological behaviors, and prognosis of gallbladder adenocarcinoma.     

The impact of divergent breed types and diets on methane emissions,rumen characteristics and performance of finishing beef cattle

This study was undertaken to further develop our understanding of the links between breed, diet and the rumen microbial community and determine their effect on production characteristics and methane (CH₄) emissions from beef cattle. The experiment was of a 2×2 factorial design, comprising two breeds (crossbred Charolais (CHX); purebred Luing (LU)) and two diets (concentrate-straw or silage-based). In total, 80 steers were used and balanced for sire within each breed, farm of origin and BW across diets. The diets (fed as total mixed rations) consisted of (g/kg dry matter (DM)) forage to concentrate ratios of either 500 : 500 (Mixed) or 79 : 921 (Concentrate). Steers were adapted to the diets over a 4-week period and performance and feed efficiency were then measured over a 56-day test period. Directly after the 56-day test, CH₄ and carbon dioxide (CO₂) emissions were measured (six steers/week) over a 13-week period. Compared with LU steers, CHX steers had greater average daily gain (ADG; P<0.05) and significantly (P<0.001) lower residual feed intake. Crossbred Charolais steers had superior conformation and fatness scores (P<0.001) than LU steers. Although steers consumed, on a DM basis, more Concentrate than Mixed diet (P<0.01), there were no differences between diets in either ADG or feed efficiency during the 56-day test. At slaughter, however, Concentrate-fed steers were heavier (P<0.05) and had greater carcass weights than Mixed-fed steers (P<0.001). Breed of steer did not influence CH₄ production, but it was substantially lower when the Concentrate rather than Mixed diet was fed (P<0.001). Rumen fluid from Concentrate-fed steers contained greater proportions of propionic acid (P<0.001) and lower proportions of acetic acid (P<0.001), fewer archaea (P<0.01) and protozoa (P=0.09), but more Clostridium Cluster XIVa (P<0.01) and Bacteroides plus Prevotella (P<0.001) than Mixed-fed steers. When the CH₄ to CO₂ molar ratio was considered as a proxy method for CH₄ production (g/kg DM intake), only weak relationships were found within diets. In conclusion, although feeding Concentrate and Mixed diets produced substantial differences in CH₄ emissions and rumen characteristics, differences in performance were influenced more markedly by breed.     

Estrogen and progesterone affect responses to malaria infection in female C57BL/6 mice

Background: Previous data from our laboratory suggest that gonadally intact C57BL/6 male mice are more likely than their female counterparts to die from Plasmodium chabaudi infection, to recover more slowly from weight loss and hematocrit loss, and to have reduced interferon-γ (IFN-γ) and interleukin-10 (IL-10) responses. Removal of the ovaries, and hence, the primary production of sex steroids in females, reverses these differences.Objective: We hypothesized that sex differences in response to P chabaudi may be mediated by differential synthesis of IFN-γ and IL-10 that is influenced by estrogen, progesterone, or both.Methods: C57BL/6 female mice (n = 200; n = 10/time point/treatment/experiment) were ovariectomized and implanted with a 21-day controlled-release pellet containing either 0.1 mg of 17β-estradiol (E₂), 10 mg of progesterone (P₄), 0.1 mg of E₂ plus 10 mg of P₄, or cholesterol (placebo). Females were inoculated with 10⁶P chabaudi-infected erythrocytes. Body mass, body temperature, hematocrit, parasitemia, cytokine production, and antibody responses were monitored 0, 3, 5, 7, 10, 14, and 21 days postinoculation.Results: Administration of E₂, either alone or in combination with P₄, mitigated infection-induced weight loss, hematocrit loss, and hypothermia, compared with females receiving placebo pellets (P < 0.05 in each case). Hormone treatment did not affect levels of parasitemia. Females administered E₂ alone or in combination with P₄ produced 4 to 7 times higher IFN-γ and IL-10 during peak parasitemia than did females implanted with pellets containing either P₄ alone or placebo (P < 0.05 in each case). Exposure to E₂, either alone or in combination with P₄, increased anti-P chabaudi immunoglobulin G (IgG1) responses and the ratio of IgG1 to IgG2c (P < 0.05 in each case).Conclusion: This animal study suggests that physiological levels of estrogen, rather than progesterone, enhance immunity and, possibly, protect females from disease symptoms during malaria infection.     

Biochemical studies on the lipid content ofTilapia nilotica andSparus auratus

1. Seasonal variations of total lipids, free fatty acids, triglycerides, phospholipids and cholesterol content of the freshwater fishTilapia nilotica and the marine fishSparus auratus were investigated.2. Male fish ofS. auratus showed higher muscular and hepatic total lipids and hepatic free fatty acids than those ofT. nilotica (P < 0.05).3. The mean differences in gonadal male lipids of the two species were not significant.Tilapia nilotica female fish showed a significantly higher content of hepatic free fatty acids, phospholipids and cholesterol (P < 0.01, 0.01, 0.05respectively) and gonadal total lipids, triglycerides, and cholesterol (P < 0.05) than those ofS. auratus females.4. In contrastS. auratus females exhibited higher muscular total lipids, triglycerides, phospholipids and cholesterol content (P < 0.01, 0.05, 0.02, 0.05, respectively) and gonadal phospholipids (P < 0.05) than those of theT. nilotica females.5. In general hepatic and gonadal lipids of freshwater fishT. nilotica were higher than those of the marine fishS. auratus, and in contrast the marine fish contained higher muscular lipids than the freshwater fish.     

Survival in air of Mytilus trossulus following long-term exposure to spilled Exxon Valdez crude oil in Prince William sound

Mussels, Mytilus trossulus, were sampled in 1996 from beaches in Prince William Sound (PWS) which contained residual oil resulting from the Exxon Valdez oil spill of March 1989, and from one beach which had been lightly oiled in 1989, but contained no residual oil in 1996. The latter mussels served as un-oiled references. Mussels were also collected from Tee Harbor, Southeast Alaska, to be used as an additional reference group. Where the size of the individuals in the resident population would permit, two size groups were sampled, 32–35 and 18–20 mm in length. Polynuclear aromatic hydrocarbon (PAH) concentrations in mussel tissue, and air survival time were determined for each group of mussels. Total PAH concentrations were significantly greater in tissue of mussels from oiled beds (0.6–2.0 μg g⁻¹) than from references (0.01–0.12 μg g⁻¹) (P<0.01). Oil-exposed mussels had significantly lower LT₅₀ values (P<0.05) for air survival than reference groups. Tolerance of small mussels to air exposure was significantly greater (P<0.01) than large mussels in both the unoiled reference and oil exposed groups.     

Sedation or anaesthesia decrease the stress response to electroejaculation and improve the quality of the collected semen in goat bucks

Electroejaculation (EE) is stressful and probably painful; thus the administration of anaesthesia is recommended to decrease those negative effects. However, anaesthesia has a direct risk of provoking death, but sedation is less risky than anaesthesia. At the same time, α2-adrenergic agonists may improve semen quality. Therefore, the aim of the present study was to compare the physiological and behavioural responses indicative of stress and possibly pain, and the semen quality in electroejaculated untreated, anaesthetised or sedated goat bucks. Semen was collected from eight bucks using three different procedures in all them (EE in untreated bucks, EE under sedation or EE under general anaesthesia). The number of vocalizations during EE and the behavioural pattern before and after procedures were recorded. Pain visual analogue scale (VAS) score was also determined during EE. Rectal temperature, heart rate, serum cortisol concentration, biochemical and haematological parameters were measured before and after each procedure, and sperm characteristics were determined. Bucks vocalised more often when untreated than sedated or anaesthetised (P<0.02). The pain VAS score was greater when bucks were untreated than sedated or anaesthetised (P<0.002). The rectal temperature, heart rate, total protein, albumin and haemoglobin concentrations were greater when bucks were untreated than anaesthetised or sedated (P<0.02). Serum cortisol increased after EE (P=0.0006), without differences between procedures. The frequency and duration of lying down after EE were greater when bucks were anaesthetised than sedated or untreated (P<0.05), and were also greater when bucks were sedated than untreated (P<0.05). The number of times that the animal tried to stand up after EE was greater when bucks were anaesthetised than sedated or untreated (P<0.02). The sperm mass motility was greater when bucks were anaesthetised or sedated than when they were untreated (P=0.048). When animals were sedated, the ejaculate contained more spermatozoa with functional plasma membrane (P=0.03) and morphologically normal (P=0.05) than when they were untreated. In conclusion, general anaesthesia and sedation decreased the stress and probably the pain response provoked by EE and especially sedation improved the quality of the semen collected.     

Effects of feeding programme on the performance and energy balance of nulliparous rabbit does

A total of 190 rabbit females were used to evaluate five feeding programmes from 9 weeks of age to the first parturition: CAL, fed ad libitum with a control diet (C: 11.0 MJ digestible energy (DE) and 114 g digestible protein (DP)/kg dry matter (DM)) until first parturition; CR, fed ad libitum with C diet until 12 weeks of age and then C diet restricted (140 g/day) until first parturition; F, fed ad libitum with a low-energy, high-fibre diet (F: 8.7 MJ DE and 88 g DP/kg DM) until first parturition; FC, fed with F diet ad libitum until 16 weeks of age, and C diet ad libitum until first parturition; FCF, fed with F diet ad libitum until 16 weeks of age, then C diet ad libitum until 20 weeks and then F diet ad libitum until first parturition. The rabbits were artificially inseminated at 18 weeks of age. CAL group had a higher mortality rate compared with the other groups between 9 and 12 weeks of age (34% v. 3%; P < 0.05) and during the last 3 weeks of first pregnancy (14% v. 3%; P < 0.05). The CAL and FC females presented higher BW and perirenal fat thickness (PFT) than CR females at 11 days of pregnancy (+0.41 kg and +0.6 mm; P < 0.05), with F females showing medium values. The type of feeding procedure did not affect the fertility rate of young females at first artificial insemination. Differences in BW disappeared at parturition, when only CAL females presented a greater PFT than CR and FC females (+0.3 mm; P < 0.05). In comparison with FCF, CAL females had smaller and thinner live born litters (−2.5 kits and −139 g, respectively; P < 0.05), with CR, F and FC females showing medium values. The low number of kits born alive for CAL females was because of their lesser total number of kits born (−1.7 kits; P < 0.05) and the greater mortality of their litters at birth (+13.9%; P < 0.05) compared with FCF females. Non-esterified fatty acid was higher in the blood of females fed C diet (CAL and CR) than in others at partum day (on average +0.15 mmol/l; P < 0.05). In conclusion, the ad libitum use of diets for lactating rabbit does throughout the rearing period could lead young rabbit females to present a higher risk of early death and smaller litter size at first parturition. Feed restriction or earlier use of suitably fibrous diets led females to achieve the critical BW and fat mass at first mating to ensure reproduction.     

Purification and characterization of phosphorylase from tubers ofDioscorea dumentorum

Phosphorylase from tubers ofDioscorea dumentorum was fractionated by (NH₄)₂SO₄ precipitation and further purified to apparent homogeneity. Two forms of phosphorylase, Dd₁ and Dd₂ were obtained with different K_m, optimum temperatures and pH values. They obeyed Michaelis-Menten kinetics, they were activated by AMP, Mg²⁺ and Ca²⁺ but inhibited by ATP, ADP, ADP-glucose and Na₂SO₄. The molecular masses found for Dd₁ and Dd₂ were 102 000 and 195 000 respectively. SDS gel electrophoresis indicated that Dd₂ is a dimer and Dd₁ is a monomer. Both phosphorylase forms contained pyridoxal-5′-phosphate as their prosthetic group, which was essential for their activity. Dd₂ is more active in starch synthesis while Dd₁ is more active in starch degradation. The affinity of the enzyme forms for P_i is not a measure of the rate of glucan degradation. The decline in activities of the enzymes between pH 5.5 and 7.5 was due to unsuitable ionic forms of the enzymes and not due to irreversible denaturation. Both forms of phosphorylase showed double displacement reaction mechanism in direction of phosphorolysis, while in direction of synthesis, sequential mechanism was indicated. Indoleacetic acid activated the enzyme forms in direction of starch degradation but acted as an inhibitor in direction of glucan synthesis. The results of this study suggest that Dd₂ may have some synthetic function while Dd₁ has a degradative role. The effect of pH on the phosphorylase activity suggests histidine as the amino acid residue around the active site that might be involved in enzyme catalysis.     

Proportion of mated females, female mating experience, and sex ratio of the osmund sawfly, Strongylogaster osmundae (Hymenoptera, Tenthredinidae)

The proportion of mated females (M _f) of the osmund sawfly, Strongylogaster osmundae, and the sex ratio of the eggs they deposited (r, proportion of males) were estimated in the wild by collecting egg masses. The proportion of mated females at oviposition varied from 0 to 1.0. M _f was high (often 1.0) among the females that emerged after hibernation, and lower in the subsequent generations. Mated females of the hibernated generation deposited equal numbers of eggs of both sexes. Mated females of the first and subsequent generations produced more female than male eggs. These results qualitatively agreed with the prediction provided by an evolutionarily stable strategy (ESS) model (if M _f < 1 then r < 0.5). However, the quantitative prediction provided by the model [M _f (1 − r) = 0.5] was not always observed in the wild, especially where the population density and M _f were high. The value of r was often lower than the predicted one. The following simple hypothesis was tested by experimentation: “Females that encounter males frequently estimate the proportion of mated females to be high and deposit eggs with a 1:1 sex ratio.” However, results did not support this hypothesis. Females that copulated soon after emergence and were courted by males two or more times did not show a higher offspring sex ratio than those which mated 1 or 2 days after emergence and experienced no other sexual encounter. Another mechanism for determination of r is suggested, and the reason why the population sex ratio of sawflies is often female-biased (r < 0.5) is discussed.     

Divergent selection for residual feed intake in group-housed growing pigs: characteristics of physical and behavioural activity according to line and sex

The aim of the study was to assess the impact of selection for residual feed intake (RFI) on the behavioural activity of lines divergently selected for RFI during seven generations. In all, six successive batches from the seventh generation of selection were raised in collective pens equipped with a single-place electronic feeder (SEF) from 10 weeks of age to 100 kg BW. Each batch included four groups of 12 pigs: high RFI (RFI⁺) castrated males, RFI⁺ females, low RFI (RFI⁻) castrated males, RFI⁻ females. At 17 weeks of age, health criteria were evaluated using a gradient scale for increased severity of lameness, body lesions, bursae and tail biting. Individual behavioural activities were recorded by 24-h video tape on the day after health evaluation. The investigative motivation towards unfamiliar objects was quantified at 18 weeks of age. The daily individual feeding patterns were computed from SEF records during the 4 weeks surrounding 12, 17 and 22 weeks of age. All pigs spent significantly most of their time lying in diurnal (80% of total scan) and nocturnal (>89%) periods. The RFI⁻ pigs showed a lower proportion of health problems (P<0.01) than RFI⁺ pigs. The RFI⁻ pigs used the SEF less than the RFI⁺ pigs, in diurnal (5.3% v. 6.4% of video scans, P<0.05) and nocturnal periods (3.6% v. 4.5% of video scans, P<0.05). This was confirmed by a significantly lower daily number and duration of visits to the SEF computed from the SEF data. The feeding activity measured from the video recording was significantly correlated (R>0.34; P<0.05) with feeding patterns computed from the SEF. The RFI⁻ pigs spent less time standing over the 24-h period (9.7% v. 12.2% of scans, i.e. 35 min/day, P<0.05). In terms of energy costs, this amounted to 14% of the line difference in terms of daily metabolizable energy intake. The castrated males used the SEF more than females, especially at night (4.7% v. 3.4% of total scans, P<0.05), whereas females displayed greater investigation of their environment (7.7±0.3% v. 6.6±0.2% of total scans, P<0.05) and the novel objects (10.7% v. 4.9% of total scans, P<0.05). In conclusion, the lower physical activity associated with reduced energy expenditure in RFI⁻ pigs compared with RFI⁺ pigs contributed significantly to their improved efficiency and was not related to worsened health scores.     

Study on immune regulation in Hyriopsis cumingii Lea: Effect of pearl-nucleus insertion in the visceral mass on immune factors present in the hemolymph

This study was aimed at elucidating the mechanism of immune responses in fresh water mussels during pearl culture. Alpha-2 macroglobulin gene (α₂M) expression, acid phosphatase (ACP) and superoxide dismutase (SOD) activities, and hemocyte counts were evaluated after inserting a pearl nucleus into the visceral mass of Hyriopsis cumingii Lea (H. Lea). We selected 60 H. Leas and randomly assigned them to 2 groups (each group contained 3 replicates of 10 individuals), and individuals among one group were treated by inserting pearl nucleus into the visceral mass. Real-time quantitative polymerase chain reaction (Q-PCR) was used to evaluate α₂M gene expression, and the activities of ACP and SOD in hemocytes and serum were determined after 1, 2, 3, 5, and 10 days after nucleus insertion. Hemocyte morphologies and numbers on the 5th day after insertion were studied using phase-contrast microscope (PCM), optical microscope and flow cytometry (FCM). All observations suggested that the insertion of the pearl nucleus in the visceral mass had a significant effect on α₂M gene expression, ACP and SOD activities, and hemocyte characteristics. The α₂M gene expression was sharply up-regulated on the 3rd day after nucleus insertion, and it was significantly higher in the test groups on the 3rd, 5th, and 10th days than those in the control groups (P < 0.05). On the 1st to 3rd after treatment, ACP activity in the test group was higher than that in the control group (P < 0.05). SOD activity in the serum was remarkably higher in the test groups than in the control group, and exhibited significant differences on the 3rd, 5th, and 10th days (P < 0.05). However, the SOD activity in hemocytes was lower in the test group than in the control group, and it exhibited significant differences on all days, except on the 3rd day (P < 0.05). The hemocytes were divisible into 2 types: granulocytes (GR) and hyalinocytes (HY). The hemocyte morphology, protuberances, vesicle-like bodies, and density increased significantly (P < 0.05), and the number of GR increased, while that of HY decreased after nucleus insertion. These results indicated that the insertion of pearl nucleus enhanced the immune response in H. Lea.     

Estradiol and progesterone receptor levels in human breast cancer in relation to cytosol and plasma estrogen level

Estradiol receptor (ER) and progesterone receptor (PR) content along with the cytosol and plasma estrone and estradiol levels in 15 premenopausal and 26 postmenopausal women with breast cancer in different clinical stages (T₁₂₃, N₀₁, M₀) were measured. ER-positive tumor frequency and the ER content tended to be higher in postmenopausal than in premenopausal patients. There was no evidence for a relationship between high cytosol estrogen levels and low receptor measurements. The estrogen concentration was higher in ER-positive tumor cytosols than in those of ER-negative tumors; the differences were significant in postmenopausal women, only, with P < 0.05 for estrone and P < 0.01 for estradiol values. Twelve pairs of tumor and normal tissue from the same breast, were also studied: seven of which contained ER-positive and five ER-negative tumors. The ER-positive tumors showed a clear trend to higher estradiol content as compared to the corresponding normal tissues. The circulating level of estradiol in postmenopausal women, was higher (P < 0.05) in ER-positive tumors than that in ER-negative tumors. Our results indicate that: (a) false negative ER assays are not likely to be due to the presence of endogenous estrogens, (b) higher amounts of estrone and estradiol are contained in ER-positive tumors than in negative ones.     

The effect of dietary addition of nitrate or increase in lipid concentrations,alone or in combination,on performance and methane emissions of beef cattle

Adding nitrate to or increasing the concentration of lipid in the diet are established strategies for reducing enteric methane (CH₄) emissions, but their effectiveness when used in combination has been largely unexplored. This study investigated the effect of dietary nitrate and increased lipid included alone or together on CH₄ emissions and performance traits of finishing beef cattle. The experiment was a 2×4 factorial design comprising two breeds (cross-bred Aberdeen Angus (AAx) and cross-bred Limousin (LIMx) steers) and four dietary treatments (each based on 550 g forage : 450 g concentrate/kg dry matter (DM)). The four dietary treatments were assigned according to a 2×2 factorial design where the control treatment contained rapeseed meal as the main protein source, which was replaced either with nitrate (21.5 g nitrate/kg DM); maize distillers dark grains (MDDG, which increased diet ether extract from 24 to 37 g/kg DM) or both nitrate and MDDG. Steers (n=20/dietary treatment) were allocated to each of the four treatments in equal numbers of each breed with feed offered ad libitum. After 28 days adaptation to dietary treatments, individual animal intake, performance and feed efficiency were recorded for 56 days. Thereafter, CH₄ emissions were measured over 13 weeks (six steers/week). Increasing dietary lipid did not adversely affect animal performance and showed no interactions with dietary nitrate. In contrast, addition of nitrate to diets resulted in poorer live-weight gain (P<0.01) and increased feed conversion ratio (P<0.05) compared with diets not containing nitrate. Daily CH₄ output was lower (P<0.001) on nitrate-containing diets but increasing dietary lipid resulted in only a non-significant reduction in CH₄. There were no interactions associated with CH₄ emissions between dietary nitrate and lipid. Cross-bred Aberdeen Angus steers achieved greater live-weight gains (P<0.01), but had greater DM intakes (P<0.001), greater fat depth (P<0.01) and poorer residual feed intakes (P<0.01) than LIMx steers. Cross-bred Aberdeen Angus steers had higher daily CH₄ outputs (P<0.001) but emitted less CH₄ per kilogram DM intake than LIMx steers (P<0.05). In conclusion, inclusion of nitrate reduced CH₄ emissions in growing beef cattle although the efficacy of nitrate was less than in previous work. When increased dietary lipid and nitrate inclusion were combined there was no evidence of an interaction between treatments and therefore combining different nutritional treatments to mitigate CH₄ emissions could be a useful means of achieving reductions in CH₄ while minimising any adverse effects.     

Effects of founder population size on the performance of Orius laevigatus (Hemiptera: Anthocoridae) colonies

Orius laevigatus (Hemiptera: Anthocoridae) is a key predator of thrips and is mass reared in large numbers for use in biological control. The aim of this study was to evaluate the effect of founder population size on the biological and behavioral performance of O. laevigatus over time. Laboratory lines were started from 1, 10 and 50 founder couples from 750 adults collected in the field and their performance was evaluated at the 5th–6th and 10th–11th generations. Adaptation to the captive rearing situation occurred in the 10 and 50 founder couples lines while it failed in the 1 founder couple line. The intrinsic rate of natural increase (r_m) increased and the period for doubling the population (D) decreased over the generations in the 10 and 50 founder couples lines, while (r_m) decreased and (D) increase in the 1 founder couple line. Also, consumption of Frankliniella occidentalis prey was significantly lower for females from the 1 founder couple line at the 5th generation compared to females from the 10 and 50 founder couples lines. Females of laboratory lines of all founder couples did not respond to odours from thrips infested plants during the 5th and 10th generations, whereas wild females strongly reacted to these odours. We suggest that the lack of reaction to infested plant volatiles may be due to the artificial rearing method where mass reared predators do not experience an infested crop. The results showed that the 1 founder couple line differed from the 10 and 50 founder couples lines, suggesting that bottlenecking had an effect at that level. However, no difference was found between the 10 and 50 founder couples lines which suggest that these founder numbers can be used to start laboratory-reared O. laevigatus lines without a significant loss in quality of its relevant biological characteristics.     

Retinoic acid can enhance the stimulation by thyroid hormone of heme oxygenase activity in the liver of thyroidectomized rats

The effects of retinoic acid (RA) (50 μg/100 g body wt. per day) on hepativ heme oxygenase activty, δ-aminolevulinate synthase (ALAS) activity and on cytochrome P-450 content were determined in thyroidectomized rats treated with T₃ (10 μg/100 g body wt. per day) or diluent. RA, when administered for 3 days, failed to influence significantly the activity of either heme oxygenase or ALAS, however, the retinoid depleted hepatic cytochrome P-450 content by 17% (P < 0.01) and microsomal heme content by 47% (P < 0.001). T₃ administration enhanced heme oxygenase activity by 72% (P < 0.001) and ALAS activity by 251% (P < 0.001) above levels in diluent treated controls and depleted cytochrome P-450 levels by 55% (P < 0.001) and heme levels by 75% (P < 0.001). When RA and T₃ were administered together, the retinoid markedly enhanced the T₃ stimulation of heme oxygenase activity; 173% above controls (P < 0.001), and 61% above T₃ alone (P < 0.001). However, RA failed to influence the effect of T₃ on ALAS activity or cytochrome P-450 depletion. The results indicate that RA can influence the levels of hepatic cytochrome P-450 and can modulate the stimulation of heme oxygenase activity by thyroid hormone in vivo.     

Characteristics of Korean-Saanen goat milk caseins and somatic cell counts in comparison with Holstein cow milk counterparts

Characteristics of α- and β-casein fractions in the milk of Korean-Saanen goats were compared with those of Holstein cow milk using capillary electrophoresis (CE) analysis. The αs₁-CN content of the Saanen goat milk samples varied from 2.4% to 9.3% of total proteins. Total αs-CN content of the goat milk varied from 10.1% to 17.0%. Total β-CN content containing β₁-CN and the β₂-CN varied from 49.6% to 61.0% of total proteins. Average αs-CN to β-CN ratio of the Saanen goat milk from different farms was 0.24 ± 0.04, ranging from 0.17 to 0.33. The αs-CN (αs₁-CN + αs₀-CN) to β-CN (β_A1-CN + β_A2-CN) ratio of Holstein cow milk was 0.81, which was much higher than that of Korean-Saanen goat milk. The goat milk samples having more than 1.5 million cells/ml somatic cell counts (SCC) contained higher αs-CNs (P < 0.01) and lower β-CNs (P < 0.05) contents than milks with <1.5 million SCC. This resulted in a higher αs-CN to β-CN ratio (P < 0.01) in the milk with >1.5 million SCC.     

Summer heterothermy in Rafinesque’s big-eared bats (Corynorhinus rafinesquii) roosting in tree cavities in bottomland hardwood forests

Many small mammals are heterothermic endotherms capable of maintaining an elevated core body temperature or reducing their thermoregulatory set point to enter a state of torpor. Torpor can confer substantial energy savings, but also incurs ecological costs, such as hindering allocation of energy towards reproduction. We placed temperature-sensitive radio transmitters on 44 adult Rafinesque’s big-eared bats (Corynorhinus rafinesquii) and deployed microclimate dataloggers inside 34 day roosts to compare the use of torpor by different sex and reproductive classes of bats during the summer. We collected 324 bat-days of skin-temperature data from 36 females and 4 males. Reproductive females employed fewer torpor bouts per day than non-reproductive females and males (P < 0.0001), and pregnant and lactating females had higher average (P < 0.0001) and minimum (P < 0.0001) skin temperatures than non-reproductive females. Pregnant females spent less time torpid (P < 0.0001) than non-reproductive females, but lactating females used relatively deep, long torpor bouts. Microclimates varied inside tree species with different configurations of entrances to the roost cavity (P < 0.0001). Bats spent more time torpid when roosting in water tupelo (Nyssa aquatica) trees possessing only a basal entrance to the cavity (P = 0.001). Of the tree species used as roosts, water tupelo cavities exhibited the least variable daytime and nighttime temperatures. These data demonstrate that use of summer torpor is not uniform among sex and reproductive classes in Rafinesque’s big-eared bat, and variation in microclimate among tree roosts due to species and structural characteristics facilitates the use of different thermoregulatory strategies in these bats.     

Effects of Yucca schidigera extract on fermentation and degradation of steroidal saponins in the rumen simulation technique (RUSITEC)

A rumen simulation technique (RUSITEC) apparatus with eight 940 ml fermentation vessels was used to study the effects of the steroidal saponins in Yucca schidigera extract (YE) on ruminal microbial activity and saponin degradation. The YE contained approximately 4.4% (w/w) saponin, as smilagenin equivalents, and was included at 0 (control) or 0.5 mg ml⁻¹ (n=4) in the McDougall's buffer infused continuously into the vessels (dilution rate=0.75 day⁻¹). Each vessel received 5 g chopped alfalfa hay and 5 g concentrate (as-fed basis) daily for 22 days. Ammonia concentrations were lower (P<0.05) in effluent from vessels receiving YE than from controls for the first half of the study, but did not differ thereafter. Total amounts of VFA in effluent were not affected (P>0.05) by YE, but molar proportions of iso-butyric and iso-valeric acids were lower (P<0.05) in the YE vessels than in the controls in the first half of the experiment. Yucca extract at 0.5 mg ml⁻¹ did not affect (P>0.05) dry matter disappearance (DMD) from hay or from concentrate, nor did it affect total gas or methane production, or bacterial numbers (total or cellulolytic populations) in homogenates prepared from fermenter vessel liquid and feed particles. Protozoal numbers in the homogenates were substantially reduced (P<0.01) by YE (at 0.5 mg ml⁻¹), protease activity was increased (P<0.05), deaminase activity and activity against Ala₂ were unaffected (P>0.05) and activity against Ala₅ was reduced by 25% (P>0.05). When the homogenates from control and YE-supplemented (0.5 mg ml⁻¹) vessels were used to inoculate roll tubes containing 0 or 5 mg ml⁻¹ of YE, fewer colonies developed (P<0.01) in roll tubes containing YE than in those without YE, irrespective of the source of inoculum. Homogenates were also assayed for saponin degradation and for protease, peptidase and deaminase activities. Inoculum from the vessels receiving YE degraded saponin slightly during a 2 h incubation. Yucca extract at 0.5 mg ml⁻¹ altered proteolytic activity and reduced protozoal numbers, but did not affect DMD or bacterial activity, and did not induce resistance to YE at a concentration of 5 mg ml⁻¹.     

The female reproductive system of the eastern Australian scorpion

The reproductive system of the female Urodacus manicatus (Scorpionidae) is described. Situated on the ventral side of the ovariuterus tubes are buds and diverticulae belonging to three developmental phases: (1) Bud-like, rudimentary diverticulae that will form future generations. (2) Embryonic diverticulae that will house the present generation. (3) Degenerating (= 'post-partum') diverticulae that contained the previous generation of juveniles just born. The smallest buds could be identified only by scanning electron microscopy of the ovariuterus tube. The various diverticulae were counted and their dimensions were measured. Based on the average number of the embryonic diverticulae, it appears that the average number of young that can be produced by a female during a single parturition is 16.8. This number does not appear to increase significantly with the growth of the female.