Effect of Leptin on In Vivo Goat Embryo Production

The aim of this study was to evaluate the effect of leptin administration during superovulation on in vivo goat embryo production. Ten mature does were superovulated with 133 mg follicle‐stimulating hormone (FSH) i.m. in six descending doses at 12‐h intervals. The goats received 4.8 μg/kg human recombinant leptin s.c. (leptin group, n = 5) or phosphate‐buffered saline (PBS) (control group, n = 5) with the first and second FSH doses. The does were mated and subjected to embryo collection by transcervical technique 6 days later. The total number of cells per embryo and the number of cells with fragmented DNA were assessed in selected blastocysts by combining Hoechst 33342 and terminal dUTP nick‐end labelling (TUNEL) staining. Plasma concentrations of oestradiol (E₂) and progesterone (P₄) were determined by electrochemiluminescence from the day of FSH treatment, on the day of superovulatory oestrus and on the day before embryo collection. Compared with the control group, the does that received leptin had a higher number of transferable embryos (p < 0.005), fewer embryos classified as degenerated (p < 0.001) and fewer TUNEL‐positive cells/blastocyst (p < 0.001). The number of transferable embryos was positively correlated with E₂ concentrations on day of oestrus (r = 0.562; p < 0.01) and P₄ concentrations on the day of embryo collection (r = 0.912; p < 0.001). We concluded that in vivo leptin administration during FSH treatment improved embryo quality and affected ovarian steroidogenesis in superovulated goats.     

Comparison of Antral and Preantral Ovarian Follicle Populations Between Bos indicus and Bos indicus‐taurus Cows with High or Low Antral Follicles Counts

The objective was to compare populations of antral and pre‐antral ovarian follicles in Bos indicus and Bos indicus‐taurus cows with high and low antral follicle counts. Nelore (Bos indicus, n = 20) and Nelore X Angus (1/2 Bos indicus‐taurus, n = 20) cows were subjected to follicular aspiration without regard to the stage of their oestrous cycle (day of aspiration = D0) to remove all follicles ≥3 mm and induce growth of a new follicular wave. Ovaries were examined by ultrasonography on D4, D19, D34, D49 and D64, and antral follicles ≥3 mm were counted. Thereafter, cows were assigned to one of two groups: high or low antral follicular count (AFC, ≥30 and ≤15 antral follicles, respectively). After D64, ovaries were collected after slaughter and processed for histological evaluation. There was high repeatability in the numbers of antral follicles for all groups (range 0.77–0.96). The mean (±SD) numbers of antral follicles were 35 ± 9 (Bos indicus) and 38 ± 6 (Bos indicus‐taurus) for the high AFC group and 10 ± 3 (Bos indicus) and 12 ± 2 (Bos indicus‐taurus) follicles for the low AFC. The mean number of preantral follicles in the ovaries of Bos indicus‐taurus cows with high AFC (116 226 ± 83 156 follicles) was greater (p < 0.05) than that of Bos indicus cows (63 032 ± 58 705 follicles) with high AFC. However, there was no significant correlation between numbers of antral and preantral follicles.     

Effect of Breeding Activity on the Microflora of the External Genitalia and in the Semen of Stallions,and the Relationship Between Micro‐organisms on the Skin and on the External Genitalia

A possible role of breeding activities in the composition of the microbial population in stallions' external genitalia (EG) and the relationship between micro‐organisms colonizing the skin of the abdomen and the ones colonizing the EG have not been studied. In experiment 1, EG microbiological samples were collected from 41 stallions used for both natural cover and semen collection (BST) and from 18 non‐breeding stallions (NBST). A higher (p < 0.05) frequency of isolation of potentially pathogenic species was found for BST. Age did not influence number of micro‐organism species isolated both in BST and NBST. In experiment 2, the microbial content of the EG and semen was compared in 23 BST. Most micro‐organisms isolated from the EG were present in semen, albeit with a numerically lower prevalence. In 7 stallions, six microbial species isolated from semen were absent from the EG cultures, suggesting contamination by the operator. In experiment 3, a numerically higher number of micro‐organism species was isolated from the EG of 31 stallions, than from their skin of the ventral abdomen in contact with the penis or from the skin of the thorax. With the sole exception of Escherichia coli, potentially pathogenic bacteria were only isolated from the EG but not from the skin. Results suggest that breeding activity increased the number of species colonizing the EG; most species isolated from the EG were also found in semen even if with a lower frequency, and additional semen contamination seemed to occur during its manipulation. Many micro‐organism species of the skin were also isolated from the penis, but independently of being or not in contact with the penis, skin did not seem to provide an adequate environment for the growth of potentially pathogenic bacteria that were isolated from EG, with the sole exception for E. coli.     

MALDI‐MS Lipid Profiles of Oocytes Recovered by Ovum Pickup from Bos indicus and 1/2 indicus × taurus with High vs Low Oocyte Yields

The aim of the present study was to compare the lipid profile in oocytes of indicus and 1/2 indicus × taurus cows with high and low antral follicle count (AFC)/oocyte yields. After an OPU procedure (D0), antral follicles ≥3 mm were counted by ultrasonography (D4, 19, 34, 49, 64), and cows were assigned to groups with either high AFC (≥30 follicles; indicus, NH group; 1/2 indicus × taurus, AH group) or low AFC (≤15 antral follicles; indicus, NL group; 1/2 indicus × taurus, AL group). The lipid profiles of the oocytes were determined by MALDI‐MS. For GI, GII and GIII oocytes, the indicus samples tend to cluster separately from the 1/2 indicus × taurus samples. The lipid species [PC (P‐38:5) + H]⁺ and/or [PC (P‐36:2) + Na]⁺, [PC (38:2) + H]⁺, [PC (38:5) + Na]⁺ and [TAG (60:8) + NH⁴]⁺ were more abundant in indicus (NH and NL groups) than 1/2 indicus × taurus. The higher lipid content in the indicus oocytes likely reflects differences in the rate of lipid metabolism and may contribute to oocyte competence and embryo development.     

Comparative digestibility of low‐quality grass hay by two breeds of cattle differing in mature live weight

The digestive capacity of the Portuguese native breed of Barrosão cattle and the Holstein–Friesian breed was measured when fed meadow hay (72–74 g CP and 641–671 g NDF/kg dry matter), offered either alone or supplemented with soya bean meal (150 g/kg dry matter), at maintenance level. Four mature cows of each breed were used. Average initial live weight (LW) was 457 and 635 kg for the Barrosão and the Holstein–Friesian cows respectively. The organic matter digestibility (OMD) of the meadow hay was higher in Holstein–Friesian than in Barrosão cows (p < 0.08) whether supplemented or not. The neutral detergent fibre digestibility of the hay was also higher in Holstein–Frisian when the hay was fed alone (p < 0.08). The soya bean meal supplementation increased the OMD and the NDFD digestibility of the total diet (p < 0.05), but not the OMD digestibility of the hay (p > 0.05). The results obtained in this study suggest a higher ability to digest fibre in the large dairy breed than in the small native breed. This suggestion is also supported by previous findings with sheep breeds largely differing in mature live weight.     

Strangulation of the small intestine by an anomalous congenital band in a yearling

Strangulating obstruction of the small intestine by anomalous mesenteric bands is an uncommon cause of colic in horses. The most commonly reported bands are mesodiverticular bands that are embryological remnants of the vitelline arteries. Despite the congenital nature of the anomaly, a wide age range of horses can be affected. This report describes a case of small intestinal strangulating obstruction caused by an unusual, anomalous congenital band attached to the ileocaecal fold in a yearling colt. Information including case background, history, clinical, laboratory, surgical and pathological findings is described.     

Preliminary observations on the tank and pond culture of the glass eels of the Australian shortfin eel, Anguilla australis Richardson

There is expanding interest in the culture of the Australian shortfin eel Anguilla australis Richardson; however, there is a lack of fundamental biology and husbandry information necessary to further develop an industry within Australia. The present study was undertaken to gain a preliminary understanding of basic husbandry requirements for rearing of juvenile A. australis (glass eels and elvers) in tanks and earthen ponds. Newly caught glass eels were successfully acclimated to culture conditions. During tank culture trials, specific growth rates (SGR) and survival rates ranged from ?2.1 to 2.8% day^?1 and 52% to 100% respectively. Glass eels weaned onto a commercial eel diet exhibited a significantly greater SGR and survival rate than those weaned onto a commercial trout diet. Glass eels weaned onto an eel diet over a 15‐day period grew slightly faster than eels weaned over a 5‐day period, but survival rates were not significantly different for each treatment. SGRs (up to 2.8% day^?1) were significantly higher for glass eels fed at 9 and 12% day^?1 than at 6% day^?1. Stocking densities between 2.5 kg m^?3 and 30 kg m^?3 did not influence either SGR or survival rates. SGRs were significantly higher for glass eels cultured at 25 °C than at lower temperatures. During pond culture trials, SGRs and survival rates ranged from 1.36 to 1.65% day^?1 and 39% to 77% respectively. The SGR and survival rates of juvenile eels stocked into ponds receiving supplementary feeding with a commercial eel diet were not significantly different to those of eels stocked into ponds that did not receive supplementary feeding.     

Growth and nutrient utilization of Murray cod Maccullochella peelii peelii (Mitchell) fingerlings fed diets with varying levels of soybean meal and blood meal

Abstract The Australian native freshwater fish Murray cod, Maccullochella peelii pellii (Mitchell), currently supports a fledgling inland aquaculture industry, which is thought to have considerable growth potential. The aim of this study was to evaluate the suitability of two alternate protein sources [blood meal (BM) and defatted soybean meal (SBM)] as substitutes for fish meal at various levels of inclusion in diets for juvenile Murray cod. The growth performance of juvenile Murray cod in response to nine isonitrogenous and isocalorific diets (50% protein, 14% lipid, 20.2 kJ g^?1) consisting of a control diet in which protein was supplied from fish meal, and test diets in which the fish meal protein was substituted at levels of 8%, 16%, 24%, and 32% with BM or SBM was evaluated from a 70‐day growth experiment. The per cent apparent dry matter (% ADC_dm) and percentage protein digestibility (% ADC_p) of the test diets were also determined using Cr₂O₃ as a marker. Survival in all the SBM dietary treatments was high but that of fish on the BM dietary treatments was significantly (P < 0.05) lower than in all the other dietary treatments. Specific growth rate (% day^?1) of Murray cod fed SBM incorporated diets ranged from 1.63 ±  0.06 to 1.78 ±  0.10 and even at the highest level tested (32% of the dietary protein from SBM) was not significantly different (P > 0.05) from the fish fed the control diet (1.65 ±  0.09). Feed conversion ratios of the SBM dietary treatments ranged from 1.36 ±  0.08 to 1.45 ±  0.07. The protein efficiency ratios and protein conversion efficiencies of Murray cod in the soybean meal treatments were also good and for a majority of the SBM diets were better than those for the control diet. Per cent ADC_dm and ADC_p of the SBM diets tested ranged from 70.6 ±  1.46 to 72.3 ±  1.81% and 88.6 ±  0.57 to 90.3 ±  0.17%, respectively, and was not significantly different (P > 0.05) from the control diet (% ADC_dm 74.3 ±  1.63; % ADC_p 91.3 ±  0.55). The reasons for significantly poor survival and growth of Murray cod reared on BM incorporated diets, and relatively poor digestibility of these diets are discussed. The study shows that for Murray cod diets in which fish meal protein is substituted up to 32% performance or carcass composition is not compromised.     

Effect of Acute Hypoxia in Trout (<Emphasis Type="Italic">Oncorhynchus mykiss</Emphasis>) on Immature Erythrocyte Release and Production of Oxidative Radicals

This paper evaluates the response of trout exposed to acute hypoxia between 8.7 mgO₂/l (controls) and 1.4 mgO₂/l. Temperature, pH, NH4, oxygen consumption rate and spleen-somatic index (SSI) were evaluated. Blood cell counts, oxidative radicals (ORs) production and immature erythrocytes were assessed to evaluate their relationship with the degree of hypoxia. Acute hypoxia induced a decrease in water pH (p < 0.05), oxygen consumption rate (60% less), SSI (55% less) and a significant increase of water ammonium concentration (p < 0.05). Haematocrit increased significantly starting at 4.8 mgO₂/l, as well as an increase in the total number of leukocytes (up to 50% in some fish). Starting at 2 mgO₂/l, swelling of erythrocytes was induced and a decrease in the potential production of ORs, showing a negative correlation to immature erythrocyte numbers. These results suggest that lower than normal oxygen concentrations may jeopardize ORs production and hence non-specific defence mechanisms in trout. High percentages of immature erythrocytes can be used as a simple and inexpensive indicator of both hypoxic events and impairment of ORs production in the absence of bleeding, haemolysis, anti-anaemia treatments and/or increased temperature.     

Effect of crude oil extracts from trout offal as a replacement for fish oil in the diets of the Australian native fish Murray cod Maccullochella peelii peelii

The efficacy of trout oil (TO), extracted from trout offal from the aquaculture industry, was evaluated in juvenile Murray cod Maccullochella peelii peelii (25.4±0.81 g) diets in an experiment conducted over 60 days at 23.7±0.8 °C. Five isonitrogenous (48% protein), isolipidic (16%) and isoenergetic (21.8 kJ g^?1) diets, in which the fish oil fraction was replaced in increments of 25% (0–100%), were used. The best growth and feed efficiency was observed in fish fed diets containing 50–75% TO. The relationship of specific growth rate (SGR), food conversion ratio (FCR) and protein efficiency ratio (PER) to the amount of TO in the diets was described in each case by second‐order polynomial equations (P<0.05), which were: SGR=–0.44TO²+0.52TO+1.23 (r²=0.90, P<0.05); FCR=0.53TO²–0.64TO+1.21 (r²=0.95, P<0.05); and PER=–0.73TO²+0.90TO+1.54 (r²=0.90, P<0.05). Significant differences in carcass and muscle proximate compositions were noted among the different dietary treatments. Less lipid was found in muscle than in carcass. The fatty acids found in highest amounts in Murray cod, irrespective of the dietary treatment, were palmitic acid (16:0), oleic acid (18:1n‐9), linoleic acid (18:2n‐6) and eicosapentaenoic acid (20:5n‐3). The fatty acid composition of the muscle reflected that of the diets. Both the n‐6 fatty acid content and the n‐3 to n‐6 ratio were significantly (P<0.05) related to growth parameters, the relationships being as follows. Percentage of n‐6 in diet (X) to SGR and FCR: SGR=–0.12X²+3.96X–32.51 (r²=0.96) and FCR=0.13X²–4.47X+39.39 (r²=0.98); and n‐3:n‐6 ratio (Z) to SGR, FCR, PER: SGR=–2.02Z²+5.01Z–1.74 (r²=0.88), FCR=2.31Z²–5.70Z+4.54 (r²=0.93) and PER=–3.12Z²–7.56Z+2.80 (r²=0.88) respectively. It is evident from this study that TO could be used effectively in Murray cod diets, and that an n‐3:n‐6 ratio of 1.2 results in the best growth performance in Murray cod.