Effect of the Interaction Between Cryoprotectant Concentration and Cryopreservation Method on Frozen/Thawed Chicken Sperm Variables

This work examines the effect of the interaction between different concentrations of two cryoprotectants – glycerol (GLY) and dimethylacetamide (DMA) – and two methods of cryopreservation – pellets produced by plunging into liquid nitrogen and gradual in‐straw freezing – on frozen/thawed chicken sperm variables. Sperm was cryopreserved using: (i) 6% DMA, following the in‐straw and the pellet methods (ii) 11% GLY, following the in‐straw and the pellet methods; and (iii) 8% GLY in the in‐straw method and 3% DMA in the pellet method (i.e. reduced cryoprotectant concentrations). When 6% DMA was used as the cryoprotectant, no differences were seen between the in‐straw and pellet methods in terms of frozen/thawed sperm variables or fertility (10.8% and 12.8%, respectively). The viability and motility variables of the frozen/thawed sperm produced using the in‐straw method with 11% GLY were higher (p < 0.05) than those recorded for the sperm preserved using the same cryoprotectant and concentration in the pellet method. However, fertility was extremely low in both groups (2.1% and 4.2% for the in‐straw and pellet methods, respectively). Finally, the use of 8% GLY in the in‐straw method returned higher sperm viability, intact acrosome and motility values than the use of 3% DMA in the pellet method (p < 0.01). No differences were seen, however, in the fertility results obtained (28.8% and 25.0%, respectively). These results suggest that cryoprotectant concentrations can be reduced and still provide acceptable fertility rates.     

Comparative Aspects of the Endotoxin- and Cytokine-Induced Endocrine Cascade Influencing Neuroendocrine Control of Growth and Reproduction in Farm Animals

Disease in animals is a well-known inhibitor of growth and reproduction. Earlier studies were initiated to determine the effects of endotoxin on pituitary hormone secretion. These studies found that in sheep, growth hormone (GH) concentration was elevated, whereas insulin-like growth factor-I (IGF-I) was inhibited, as was luteinizing hormone (LH). Examination of the site of action of endotoxin in sheep determined that somatotropes expressed the endotoxin receptor (CD14) and that both endotoxin and interleukin-Iβ activated GH secretion directly from the pituitary. In the face of elevated GH, there is a reduction of IGF-I in all species examined. As GH cannot activate IGF-I release during disease, there appears to be a downregulation of GH signalling at the liver, perhaps related to altered nitration of Janus kinase (JAK). In contrast to GH downregulation, LH release is inhibited at the level of the hypothalamus. New insights have been gained in determining the mechanisms by which disease perturbs growth and reproduction, particularly with regard to nitration of critical control pathways, with this perhaps serving as a novel mechanism central to lipopolysaccharide suppression of all signalling pathways. This pathway-based analysis is critical to the developing novel strategies to reverse the detrimental effect of disease on animal production.     

Prospective Hematologic and Clinicopathologic Study of Asymptomatic Cats With Naturally Acquired Feline Immunodeficiency Virus Infection

Prospective studies were performed over a 28- to 77-month period (median, 66 months) on 5 cats with naturally acquired feline immunodeficiency virus (FIV) infection in an attempt to correlate hematologic and Clinicopathologic changes with the emergence of clinical disease. On presentation, all cats were asymptomatic; free of opportunistic infections; and had normal complete blood counts, bone marrow morphologies, marrow progenitor frequencies, and progenitor in vitro growth characteristics. During study, 2 cats remained healthy, 2 cats showed mild clinical signs, and 1 cat developed a malignant neoplasm (ie, bronchiolar-alveolar adenocarcinoma). Although persistent hematologic abnormalities were not observed, intermittent peripheral leukopenias were common. In 3 of 5 FlV-seropositive cats, lymphopenia (< 1,500 lymphs/μL; normal reference range, 1,500 to 7,000 lymphs/μL) was a frequent finding and the absolute lymphocyte counts had a tendency to progressively decline. One of the other 2 cats had consistently low to low-normal absolute neutrophil counts (1,300 to 4,800 segs/μL; mean, 2,730 segs/μL; normal reference range, 2,500 to 12,500 segs/μL), and the remaining cat had consistently normal leukograms, except for a transient period (ie, 11 months) of benign lymphocytosis (7,200 to 13,430 lymphs/μL) early in the study. Periodic examinations of bone marrow aspirates revealed normal to slightly depressed myeloid-to-erythroid ratios with normal cellular morphology and maturation. Bone marrow abnormalities observed late in the study included mild dysmor-phic changes (ie, megaloblastic features) in 2 cats, and a significant decrease (60% of controls, P < .001) in the frequencies of burst-forming units erythroid (BFU-E) in marrow cultures of FIV-seropositive cats compared with uninfected control cats. Serum biochemical profiles were unremarkable throughout the study, with the exception of hyperglobulinemia (ie, polyclonal gammopathy) in 2 of 5 cats. Peripheral blood and bone marrow findings were of no apparent prognostic value. These results confirm the long latency between natural FIV infection and the development of life-threatening clinical disease. Chronic FIV infection, like infection with human immunodeficiency virus, can be associated with derangements in peripheral blood cell counts, as well as pertubations in marrow cell morphologies and hematopoietic progenitor frequencies before the terminal symptomatic stages of retroviral disease, when persistent cytopenias are prominent.     

Clearance of para-aminohippuric acid in wethers consuming locoweed

AIM: To validate the use of para-aminohippuric acid (PAH) as a marker for measuring blood flow in wethers consuming a mixed diet of locoweed and blue grama hay.

METHODS: Fourteen sheep, stratified by bodyweight (BW), were assigned to one of three treatments: 0.8 mg swainsonine (SW)/kg BW (HI), 0.2 mg SW/kg BW (LO), and no SW (Control). Sheep were fed various ratios of locoweed and blue grama hay to deliver SW treatments, for 28 days prior to infusion of PAH. Concentrations of SW and activities of alkaline phosphatase (Alk-P) and aspartate aminotransferase (AST) in serum were measured to confirm exposure to SW and subclinical intoxication. A single 20-ml injection of 5% PAH was delivered into the jugular vein after subclinical intoxication had been achieved. Blood samples were collected and serum analysed for PAH immediately prior to injection, then every 5 min from 5–30 min, and every 10 min from 30–60 min, following injection of PAH.

RESULTS: Effective delivery of SW was evident from the greater concentrations of SW measured in the serum of HI compared with LO animals (p<0.05). No significant differences were detected in the rate of elimination (range 0.097–0.108 L/min), elimination half-life (range 6.62–7.24 min), apparent volume of distribution for the central compartment (range 7.14–9.72 L), and clearance (range 0.73–0.92 L/min) of PAH, between treatments.

CONCLUSIONS: Subclinical intoxication with SW did not affect the pharmacokinetics of PAH. Thus, use of downstream dilution of PAH is a valid method to determine the rate of blood flow in nutrient flux experiments that involve consumption of locoweed.     

The Recipients' Parity Does Not Influence Their Reproductive Performance Following Non‐Surgical Deep Uterine Porcine Embryo Transfer

With the development of the non‐surgical deep uterine (NsDU) embryo transfer (ET) technology, the commercial applicability of ET in pigs is now possible. There are, nevertheless, many factors that influence NsDU‐ET effectiveness that need to be addressed. The aim of this study was to evaluate the effects of the weaned recipients' parity on fertility and prolificacy following NsDU‐ET. The recipients (n = 120) were selected based on their reproductive history and body condition and grouped into three categories according to their parity: primiparous sows, sows of parity 2 and sows of parities from 3 to 5. Thirty fresh embryos (morulae and unhatched blastocysts) were non‐surgically transferred into one uterine horn of each recipient. It was possible to insert the NsDU‐ET catheter through the cervix along a uterine horn in 98.3% of the recipients. The parity had no influence on the difficulty grade of the insertions or on the percentage of correct insertions. The cervix and uterine wall were not perforated during the insertions, and vaginal discharge was not observed after transfer in any of the recipients. There were no differences in the pregnancy rates (74.8%), farrowing rates (71.2%) or litter sizes (9.6 ± 3.3) between groups. Also, there were no differences between groups regarding to the piglets' birthweights or piglet production efficiency. In conclusion, these results demonstrate that weaned sows from parity 1 to 5 are appropriate to be used as recipients in NsDU‐ET programs, which increase the possibilities for the utilization of ET in the recipient farms.     

Improvement of 2D‐PAGE Resolution of Human,Porcine and Equine Follicular Fluid by Means of Hexapeptide Ligand Library

The major challenge of follicular fluid proteomic analysis is the presence of high‐abundance proteins that originate from plasma. These proteins can prevent the detection of lower abundant ones, produced locally by follicle cells and that may have important roles in follicular activity. In this study, the novel technology called hexapeptide ligand library was evaluated to enrich the low‐abundance proteins in follicular fluid of human (HFF), porcine (PFF) and equine (EFF) prior 2D‐PAGE. Our results showed that the new strategy enabled detection of many new protein spots, increased resolution and highly improved the intensity of low‐abundance proteins by 2D‐PAGE.     

Chemical Usurpation of a Nest by Paper Wasp Parasites

The paper wasp Polistes atrimandibularis is an obligatory social parasite of another Polistes species, P. biglumis bimaculatus. To control the host nest, the parasite sequentially changes the composition of its chemical signature, the cuticular hydrocarbons, during the colonial cycle. Gas chromatography-mass spectrometry of the cuticular hydrocarbons at every stage of the cycle showed that the parasite can switch on and off an entire chemical family, namely, the unsaturated hydrocarbons. In this way the parasite can match the host signature at a critical moment of the colonial cycle.     

Role of Sperm Velocity Variables Associated with Poultry Breed in ‘Last Male Precedence’

It is well known that when a hen mates with multiple roosters, it is the sperm of the last male that usually fertilizes most of the eggs (‘last male precedence’). Sperm quality varies between males within a breed, but also between breeds, and thus, sperm competitiveness after mating may depend on the breeds of the roosters involved. The aim of the present work was to identify differences in sperm competitiveness between breeds, especially with respect to motility. A multibreed mating model was used. Blue Andaluza (BA) and Black Castellana (BC) hens left for 21 days with BA and BC roosters, respectively, were then left with Black‐barred Andaluza (Bb) roosters for another 21 days (experimental groups hBA‐rBC‐rBb and hBC‐rBA‐rBb). Bb roosters (as the second breed replacing the first) fertilized the majority of eggs in both the hBC‐rBA‐rBb and hBA‐rBC‐rBb groups. The percentage of offspring sired by BA roosters (8.0%) was higher (p < 0.05) than the percentage of chicks sired by BC roosters (2.1%). The fertility of the BC hens in the hBC‐rBA‐rBb group was higher (p < 0.01) than that of the BA hens in the hBA‐rBC‐rBb group. No difference in sperm concentration was seen between the breeds. Within the rapid sperm subpopulation (sperm velocity, >50 μm/s), Bb sperm showed a higher straight‐line velocity (VSL) and average path velocity (VAP) (p < 0.05) than BC sperm. The VSL and VAP values for Bb and BA sperm were similar. In conclusion, the present results show that the sperm of the BA breed, traditionally regarded as of moderate fertility, compensates for this drawback via sperm movement characteristics that afford it an advantage in competition scenarios involving males of other breeds. The VSL and VAP of the rapid sperm subpopulation may play the most important role in securing last male precedence.