Protective effect of esterified glucomannan on aflatoxin-induced changes in testicular function,sperm quality,and seminal plasma biochemistry in rams

The aim of this study was to determine the effect of aflatoxin (AF) on spermatologic, biochemical, and testis parameters in rams, and the protective efficiency of esterified glucomannan (EG) co-administered with AF. Thirty-two Merino rams (12–14 months old) were used. The experimental design consisted of four dietary treatments. The control group was fed commercial feed. The AF group was fed with commercial feed plus 250 μg/d of total AF. The EG group received commercial feed plus 2 g/d of EG. The AF + EG group was given commercial feed plus 250 μg/d of total AF and 2 g/d of EG. There were treatment, time, and treatment-by-time interaction effects on sperm motility, abnormal spermatozoa, damaged acrosome, and dead spermatozoa (P < 0.01). The percentage of motile sperm was lower and the percentages of abnormal sperm, sperm with damaged acrosomes, and dead sperm were greater in the AF group than in the control, AF+EG, and EG groups, as from week 3 until the end of week 12 (P < 0.05). As from week 3, hyaluronidase activity in the seminal plasma increased significantly in the AF group, compared with the control. The co-administration of AF+EG was found to be effective in preventing the increase in hyaluronidase activity. As week 4, malondialdehyde (MDA) levels were significantly higher in the AF group compared with the control. The combined administration of AF+EG was found to be effective in lowering the MDA levels, increased by AF, to the levels measured in the control (P < 0.05). Although glutathione (GSH) levels were determined to have significantly decreased in the AF group in comparison to the control, it was observed that, in the group co-administered with AF and EG, particularly after week 7, the GSH levels, which had decreased owing to AF, were largely ameliorated (P < 0.05). In conclusion, AF adversely affected spermatologic, biochemical, and testis parameters, and the combined administration of EG with AF reversibly eliminated these adverse effects in rams.     

Methionine supplementation improves ram sperm parameters during liquid storage at 5 °C

The aim of this study was to investigate the effects of methionine and lipoic acid on ram sperm parameters during liquid storage (5 °C). Ejaculates collected from five Merino rams were pooled at 37 °C. Each pooled ejaculate was divided into five equal aliquots and diluted (37 °C) with five extenders, one of which was without additives, two of which contained methionine at two different doses, and the other two of which contained lipoic acid at two different doses. Sperm parameters were determined at 0, 24, 48, 72 and 96 h of liquid storage at 5 °C.     

Effect of water temperature on dietary protein requirement,growth and body composition of Asian catfish, Clarias batrachus fry

This study aimed to evaluate the protein requirement of Clarias batrachus fry, were estimated at two different water temperatures, 28 and 32 °C. The influence of dietary protein level and water temperature on body composition, weight gain, food and nutrient utilization were estimated. The Asian catfish, C. batrachus fry were fed four diets containing 28% (diet 1), 32% (diet 2), 36% (diet 3) and 40% (diet 4) protein levels and reared at two water temperatures 28 and 32 °C for 60 days. Fry fed with diet 3 containing 36% protein showed the highest mean final body weight at 32 °C. Final body weight was significantly (P<0.05) affected by dietary treatments and temperatures. Clarias batrachus fry raised at 28 °C had higher feed efficiency (93.20%) than the fry reared at 32 °C (87.58%) with 28% dietary protein level. Further, feed efficiency decreased with increase in dietary protein level. Higher daily protein retention (0.089%) observed at lower (0.0217 g) daily protein intake at 28 °C than 0.0283 g at 32 °C. While, optimal (0.0282 g) daily protein intake showed higher daily weight gain at 32 °C. Productive protein value (% PPV) was maximum (1.76%) at 32 °C than at 28 °C (0.76%). Final body lipid recorded higher value than initial body lipid at both the temperatures. Hepatosomatic index (HSI) observed to have been influenced (P<0.05) by diets and temperatures, while viscerosomatic index (VSI) affected (P<0.05) by only diets and not (P>0.05) by temperatures. The study concluded that the diet 3 containing 36% protein was optimal for growth of C. batrachus fry at both the temperatures.     

Freezability prediction of boar ejaculates assessed by functional sperm parameters and sperm proteins

The objective of this work was to look for useful predictive indicators of the potentially “good” or “poor” ability of a boar ejaculate to sustain cryopreservation by assessing both the conventional sperm quality parameters (Study 1) and the immunolabeling of three proteins involved in the physiology of the sperm cell: GLUT3, HSP90AA1 and Cu/ZnSOD (Study 2). Study 1 was carried out in three different steps during the cryopreservation process of the sperm-rich fraction of 29 Piétrain boar ejaculates (17 °C, 5 °C, and 240 min postthaw). These ejaculates were clustered based on sperm quality parameters analyzed at 240 min postthaw, obtaining 16 good freezability ejaculates (GFEs) and 13 poor freezability ejaculates (PFEs). The sperm linearity (LIN) and the straightforward (STR) indexes at 5 °C showed higher hyperactivated movement in the PFEs than in the GFEs, which suggests that analyzing these sperm kinematic parameters could be a useful tool for predicting the potential freezability of an ejaculate. This statement was demonstrated by grouping the 29 ejaculates into two clusters (A and B) based on LIN and STR values assessed after 30 min at 5 °C, which resulted in around 72% of coincidence with the GFE and PFE groups. Study 2, performed at 17 °C and 240 min postthaw, revealed no differences between GFEs and PFEs in the immunolabeling of the three proteins within a same step, in terms of location and reactivity, although reactivity was generally weaker at 240 min postthaw in both groups. Additional studies on Western blot are currently being carried out with the objective to quantify the expression of the three proteins in GFEs and PFEs in the three steps of the cryopreservation process.     

The effect of temperature on feeding and growth characteristics of the sea urchin Lytechinus variegatus fed a formulated feed

We investigated the effect of culture temperature on feed intake, absorption, organismal growth, and tissue production of Lytechinus variegatus by culturing individuals at three different temperatures representing the normal range of temperature exposure in wild populations in the northern Gulf of Mexico. Large L. variegatus (ca. 42 + 0.6 mm diameter, 36 + 1.3 g wet weight, n = 97) were collected at St. Joseph Bay, Florida, in October 2001. Eight sea urchins were held individually in 1-L containers within an 80-L aquarium with recirculated synthetic seawater at 32-ppt salinity. Three aquaria with the containers were each placed in three incubators at temperatures of 16, 22, or 28 °C for 8 weeks. Sea urchins held at 22 °C had the highest rate of feed intake. Feed intake in individuals held at 16 °C decreased significantly during the first 2 weeks of exposure and then increased to values not significantly different from those held at 28 °C by week 6. The dry matter absorption efficiency of individuals held at 28 °C was significantly higher than those held at 16 °C or 22 °C. The percentage of organic matter in the feces did not vary significantly with temperature. Individuals increased significantly in diameter, wet weight, and gonad weight at all temperatures. The wet weights of individuals held at 22 °C were significantly higher than those held at 28 °C or 16 °C, which did not differ significantly. The gut weight varied inversely with temperature. The wet weight of gonads of individuals held at 22 °C was significantly higher than those held at 28 °C, but neither differed significantly from those held at 16 °C. Production efficiencies, both organismal and gonadal, were inversely proportional to temperature, indicating that the overall metabolic cost of production increased with increasing temperatures. Organism production efficiencies were lower and gonad production efficiencies were higher than those found in small sea urchins, emphasizing that patterns of nutrient allocation vary between small and large sea urchins. Physiological processes associated with feed intake, absorption, and nutrient allocations vary with temperature, but allow the sea urchins to maintain growth and gonad production at a variety of temperatures. These data suggest that temperatures near the upper limits do not promote efficient use of resources, an important consideration for future commercial culture. Since gonad (roe) production is the ultimate goal of many aquaculture operations, gonad production efficiencies will provide a valuable tool for evaluating the efficacy of various feeds and feeding conditions on gonad production.     

Adaptive responses to fescue toxicosis under thermoneutral and heat stress conditions

This study determined the potential for short-term adaptation to fescue toxicosis and heat stress in rats. Male CD outbred rats (n=24) were implanted with temperature transmitters (Respironics, Bend, OR) to measure core temperature (Tc) and general activity. All rats were initially fed diets with ground, uninfected tall fescue seed (E−) and exposed to 21 °C (thermoneutral, TN) to establish baseline values. In Period 1, all groups were maintained at TN for 7 days, with one group fed a diet containing ground, endophyte-infected tall fescue seed (E+, approximately 165 μg ergovaline/kg BW/d) and two groups fed E− diet. Ergovaline is thought to be the primary toxin responsible for many symptoms associated with fescue toxicosis. Period 1 was followed by 7 days at 31 °C (heat stress, HS, Period 2) on the same diets. All animals were fed E− diet during the second 7 day of HS (Period 3). In the final 7 day (Period 4), E+ diet was returned to the original group and fed to one of the previously E− groups, with the third group remaining on E− diet. A 40% decrease in FI occurred with E+ treatment at TN (P<0.05), with a comparable BW reduction (P<0.05) after 4 day. Both responses worsened during HS. Treatment with E+ in Period 4 indicated that FI and BW had not adapted to fescue toxicosis. A reduction in daily Tc occurred with E+ treatment at TN (P<0.05) followed by hyperthermia during the initial stage of HS (P<0.05). Although feed intake and growth rate showed no change over time, there was a reduction in fescue toxicosis-induced hyperthermia in the heat with repeat treatment. Conditioning animals to fescue toxicosis and heat stress prior to exposure may be beneficial in reducing impacts on thermal status of the animal.     

Nutritional evaluation of treated X’pelon seed (Vigna unguiculata (L.) Walp) in the feeding of Nile tilapia (Oreochromis niloticus)

Legume seed products are used extensively in human and animal nutrition, but high levels of inclusion are often avoided as their secondary compounds can interfere with digestion and absorption of nutrients in the digestive tract. Due to the well-known benefits of some physicochemical treatments on nutritional value, this experiment was completed to assess effects of soaking and heat treatment on the nutritional value of dehulled and hulled X’pelon seeds (Vigna unguiculata (L.) Walp) to Nile tilapia (Oreochromis niloticus) fingerlings. Seeds were soaked for 16 h in a 2 g/kg sodium bisulphate solution in water. Seeds were divided into two lots, being hulled and dehulled. Three heat treatments were used to convert the seeds to meal, being 5 h of hot air flow (70 °C); autoclaving at 119 °C for 30 min to 1.05 kg/cm², and 7 h in a forced air oven at 48 °C. The resultant crude protein (CP) quality of each meal was evaluated by amino acid analysis and by a tilapia feeding study in which fingerlings were fed one of eight diets, each containing 350 g CP/kg of DM, of which seven diets were formulated with 0.80 of CP provided by fish meal and 0.20 by the X’pelon meals and one control diet was formulated with fish meal as the sole CP source. The study encompassed 9 weeks during which fingerlings were fed ad libitum. Chemical and secondary compound analysis of treated seeds showed that heat flow reduced phytic acid by 34.9% and trypsin inhibitors and hemaglutinin decreased by 94.5%, while complete elimination was obtained with autoclaving. Soaking and heat treatment are suitable for partial or complete elimination of the secondary compounds of X’pelon seeds without affecting the content and bioavailability of amino acids, with heat treatment by hot air flow the best. Partial replacement of fish meal with X’pelon meal improved growth and feed efficiency of Nile tilapia, whether the meal was treated or raw.     

Effect of feed restriction or feeding high-fibre diet during the rearing period on body composition, serum parameters and productive performance of rabbit does

This study evaluated the effect of different feeding regimes from 11 weeks of age to first parturition on feed intake, leptin, non-esterified fatty acids (NEFA) and total protein serum levels, as well as productive performance in young rabbit does. In addition, body composition was estimated by bioimpedance analysis. Thirty-six 11-week-old does were randomly distributed in three groups. The AL-C group was fed ad libitum a control diet containing 350 g neutral detergent fibre (aNDFom)/kg, 11.6 MJ digestible energy (DE)/kg and 173 g crude protein (CP)/kg, and the does were inseminated at 16 weeks of age. The R-C group was fed 150 g/d of the same diet until 16 weeks of age, one week before artificial insemination (AI) at 17 weeks of age, and then fed ad libitum. The AL-F group was fed a diet containing 475 g aNDFom/kg, 9.4 MJ DE/kg and 174 g CP/kg ad libitum, and was inseminated at 17 weeks of age. During rearing (11-16 weeks), does in the R-C group had the lowest DE (1.54 MJ/d; P<0.003) and digestible protein (DP, 17.9 g/d; P<0.001) intake, as well as the lowest protein (172 g/kg; P<0.05) and energy (5.9 MJ/kg) body contents, leptin concentration at 16 weeks of age (2.48 ng/ml; P<0.001) and fertility (P<0.02) at first AI. Daily feed intake during pregnancy and lactation, as well as prolificacy and litter weight, were similar among groups. The highest percentage of body fat was observed for all the does when were inseminated for the first time (135 g/kg; P<0.001), consistent with the highest leptin (4.48 ng/ml; P<0.001) and total protein serum levels (6.87 g/dl; P<0.001) at this time. Serum NEFA level around parturition was higher (P<0.05) in groups AL-C and R-C (1.11 and 0.85 mmol/l) than in group AL-F (0.71 mmol/l), suggesting a lower lipid mobilization that tended to improve fertility rate for AL-F does on day 11 post-parturition (P<0.09). In conclusion, feed restriction during the rearing period delays reproductive development in young rabbits. In nulliparous does, ad libitum feeding during rearing with a high-fibre diet allows a similar productive performance to that of feeding with a less fibrous diet. Nevertheless, the use of high fibre diets during rearing does not affect feed intake throughout the first pregnancy and lactation.     

Preliminary studies on cryopreservation of snakehead (Channa striata) embryos

This paper reports the findings of the ongoing studies on cryopreservation of the snakehead, Channa striata embryos. The specific objective of this study was to collect data on the sensitivity of C. striata embryo hatching rate to low temperatures at two different developmental stages in the presence of four different cryoprotectants. Embryos at morula and heartbeat stages were selected and incubated in 1 M dimethyl sulfoxide (Me₂SO), 1 M ethylene glycol (EG), 1 M methanol (MeOH) and 0.1 M sucrose solutions at different temperatures for a period of time. Embryos were kept at 24 °C (control), 15 °C, 4 °C and −2 °C for 5 min, 1 h and 3 h. Following these treatments, the embryos were then transferred into a 24 °C water bath until hatch to evaluate the hatching rate. The results showed that there was a significant decrease of hatching rate in both developmental stages following exposure to 4 °C and −2 °C at 1 h and 3 h exposure in each treatment. Heartbeat stage was more tolerant against chilling at −2 °C for 3 h exposure in Me₂SO followed by MeOH, sucrose and EG. Further studies will be conducted to find the best method to preserve embryos for long term storage.     

Cryopreservation of Greenshell™ mussel (Perna canaliculus) trochophore larvae

The Greenshell™ mussel (Perna canaliculus) is the main shellfish species farmed in New Zealand. The aim of this study was to evaluate the effects of cryoprotectant concentration, loading and unloading strategy as well as freezing and thawing method in order to develop a protocol for cryopreservation of trochophore larvae (16–20 h old). Toxicity tests showed that levels of 10–15% ethylene glycol (EG) were not toxic to larvae and could be loaded and unloaded in a single step. Through cryopreservation experiments, we designed a cryopreservation protocol that enabled 40–60% of trochophores to develop to D-larvae when normalized to controls. The protocol involved: holding at 0 °C for 5 min, then cooling at 1 °C min⁻¹ to −10 °C, holding for a further 5 min, then cooling at 0.5 °C min⁻¹ to −35 °C followed by a 5 min hold and then plunging into liquid nitrogen. A final larval rearing experiment of 18 days was conducted to assess the ability of these frozen larvae to develop further. Results showed that only 2.8% of the frozen trochophores were able to develop to competent pediveligers.     

Cryopreservation of collared peccary (Pecari tajacu) semen using different freezing curves,straw sizes,and thawing rates

The objective of this study was to verify the effect of different freezing curves, straw sizes, and thawing rates on the cryopreservation of collared peccary semen. Twelve ejaculates were obtained from captive adult males by electroejaculation, and evaluated for sperm motility, kinetic rating, viability, morphology, and functional membrane integrity. The ejaculates were diluted in a coconut water extender (ACP-116c) with egg yolk and glycerol, packaged into 0.25 mL or 0.50 mL plastic straws and cryopreserved in liquid nitrogen following a slow (−10 °C/min) or a fast (−40 °C/min) freezing curve. After one week, samples were thawed at 37 °C/1 min or 70 °C/8 s and evaluated as reported for fresh semen, and also for kinematic parameters (computerized analysis). A significant decrease in sperm motility and kinetic rating was observed after glycerol addition at 5 °C and also after thawing for all the treatments (P < 0.05). Regarding post-thaw semen variables, no differences were verified between freezing curves when the same straw size and thawing rate were taken as reference (P > 0.05). In general, values for sperm characteristics found after thawing at 37 °C were better preserved than at 70 °C (P < 0.05), both in the use of 0.25 mL or 0.50 mL straws, which were similar for semen packaging (P > 0.05). The evaluation of the kinematic parameters of sperm motility confirmed these results at values varying from 20% to 30% motile sperm for the samples thawed at 37 °C, and values fewer than 12% motile sperm for samples thawed at 70 °C (P < 0.05). In conclusion, we recommend the use of a fast freezing curve that reduces the time spent on the cryopreservation of collared peccary semen, which could be packaged both in 0.25 mL or 0.50 mL straws, but the thawing should be conducted at 37 °C/1 min.     

Influence of micronization (fine grinding) of soya bean meal and fullfat soya bean on productive performance and digestive traits in young pigs

Two trials were conducted to test the effect of micronization (very fine grinding) of soya bean meal (SBM) and fullfat soya bean (FFSB) on productive performance and digestive traits of piglets. The experimental design was completely randomized with four treatments arranged factorially (SBM and FFSB, micronized and ground). The mean particle size (MPS) was 47 and 881 μm for the SBM and 41 and 778 μm for the FFSB, micronized and ground, respectively. In trial 1 growth traits from 23 to 45 days of age and the coefficient of total tract apparent digestibility (CTTAD) of dietary components at 33 and 45 days of age were assessed. In trial 2 the coefficient of ileal apparent digestibility (CIAD) of dietary components, the pH of the gastro intestinal tract (GIT) and the weight of digestive organs and spleen were measured at 45 days of age. From 23 to 33 days of age pigs fed SBM grew faster (253 g/d versus 213 g/day; P<0.05) and were more efficient (0.87 g/g versus 0.98 g/g; P<0.01) than pigs fed FFSB. For the entire experiment (23–45 days of age) pigs fed SBM tended to grow more (360 g/day versus 324 g/day) and to eat more feed (414 g/day versus 380 g/day) than pigs fed FFSB (P<0.10). The CTTAD of crude protein (0.798 g/kg versus 0.778 g/kg), organic matter (0.864 g/kg versus 0.839 g/kg) and gross energy (0.849 g/kg versus 0.830 g/kg) were higher for pigs fed SBM than for pigs fed FFSB (P<0.001). In addition, CIAD of organic matter (0.765 g/kg versus 0.705 g/kg) and gross energy (0.761 g/kg versus 0.711 g/kg) were higher for SBM than for FFSB diets (P<0.001). The pH of the different segments of the GIT was not affected by the protein source (P>0.10). Particle size did not affect any trait studied (P>0.10). The poor performance and digestibility of pigs fed FFSB as compared to pigs fed SBM might be related to the conditions applied during processing. It is concluded that pigs fed soya bean meal perform better than pigs fed FFSB and that micronization of the soya protein sources does not affect any trait studied.     

Season of ejaculate collection influences the freezability of boar spermatozoa

The aim of this retrospective study was to evaluate whether the season of ejaculate collection influences the freezability of porcine sperm. A total of 434 ejaculates were collected from boars of six different breeds over three years (2008–2011) and throughout the four seasons of the year identified in the northern hemisphere (winter, spring, summer and autumn). The ejaculates were cryopreserved using a standard 0.5 mL straw freezing protocol. Sperm quality was assessed before (fresh semen samples kept 24 h at 17 °C) and after freezing and thawing (at 30 and 150 min post-thawing in semen samples kept in a water bath at 37 °C), according to the percentages of total motility, as assessed by the CASA system, and viability, as assessed by flow cytometry after staining with SYBR-14, PI and PE-PNA. The data, in percentages, on sperm motility and viability after freezing and thawing were obtained at each evaluation time (recovered) and were normalized to the values before freezing (normalized). The season of ejaculate collection influenced (P < 0.01) sperm quality before freezing and after thawing (recovered and normalized), irrespective of the breed of boar. Sperm quality was lower in summer, both in terms of motility and viability, and in autumn, in terms of motility, than in winter and spring. Seasonality in the normalized data indicates that the season of ejaculate collection influences sperm freezability, regardless of the season’s influence on sperm quality before freezing. Consequently, the spermatozoa from ejaculates collected during summer and, to a lesser extent, also in autumn, are more sensitive to cryopreservation than those from ejaculates collected during winter and spring.     

Methane recovery from the anaerobic codigestion of municipal sludge and FOG

The anaerobic biodegradability of a mix of municipal primary sludge (PS), thickened waste activated sludge (TWAS) and fat, oil, and grease (FOG) was assessed using semi-continuous feed, laboratory-scale anaerobic digesters operated at mesophilic (35 °C) and thermophilic (52 °C) temperature. Addition of a large FOG fraction (48% of the total VS load) to a PS + TWAS mix, resulted in 2.95 times larger methane yield, 152 vs. 449 mL methane @ STP/g VS added at 35 °C and 2.6 times larger methane yield, 197 vs. 512 mL methane @ STP/g VS added at 52 °C. The high FOG organic load fraction was not inhibitory to the process. The results of this study demonstrate the benefit of sludge and FOG codigestion.     

Sulfidogenic fluidized bed treatment of real acid mine drainage water

The treatment of real acid mine drainage water (pH 2.7-4.3) containing sulfate (1.5-3.34 g/L) and various metals was studied in an ethanol-fed sulfate-reducing fluidized bed reactor at 35 °C. The robustness of the process was tested by increasing stepwise sulfate, ethanol and metal loading rates and decreasing feed pH and hydraulic retention time. Highest sulfate reduction rate (4.6 g/L day) was obtained with feed sulfate concentration of 2.5 g/L, COD/sulfate ratio of 0.85 and HRT of 12 h. The corresponding sulfate and COD removal efficiencies were about 90% and 80%, respectively. The alkalinity produced in sulfidogenic ethanol oxidation neutralized the acidic mine water. Highest metal precipitation efficiencies were observed at HRT of 24 h, the percent metal removal being over 99.9% for Al (initial concentration 55 mg/L), Co (9.0 mg/L), Cu (49 mg/L), Fe (435 mg/L), Ni (3.8 mg/L), Pb (7.5 mg/L) and Zn (6.6 mg/L), and 94% for Mn (7.21 mg/L).     

Cryopreservation of red snapper (Lutjanus argentimaculatus) sperm: Effect of cryoprotectants and cooling rates on sperm motility, sperm viability, and fertilization capacity

Sperm cryopreservation of red snapper (Lutjanus argentimaculatus) is essentially unexplored, although many species of the Lutjanidae family are considered to be high-value commercial species. The objective of this study was to develop a species-specific cryopreservation protocol for red snapper (L. argentimaculatus) sperm by optimizing cryoprotectants and cooling rates in the cryopreservation procedure. Ten cryoprotectants at four concentrations and two freezing protocols were examined in two separate experiments. In the first experiment, toxicity studies of dimethyl sulfoxide (DMSO), glycerol, propylene glycol (PG), ethylene glycol (EG), formamide, methanol, ethanol, sucrose, trehalose, and dimethylacetamide (DMA) on sperm motility were performed. Semen diluted 1:1 in Ringer solution were exposed to cryoprotectants at four final concentrations of 5%, 10%, 15%, or 20% for periods of 10, 20, 30, 40, 50, 60, 90, and 120 min at room temperature (25 °C). The cryoprotectants and concentrations that showed the least toxic effect on sperm motility were selected for cryopreservation trials. In the second experiment, selected cryoprotectants were then assessed for freezing capacity of sperm as follows: DMSO 5% and 10%, PG 5% and 10%, EG 5% and 10%, ethanol 5%, and methanol 5%. Semen was diluted 1:1 in Ringer solution and equilibrated with selected cryoprotectants for 10 min at room temperature. Sperm were frozen in a controlled-rate programmable freezer at four cooling rates of 3, 5, 10, and 12 °C/min from an initial temperature of 25 °C to final temperatures of −40 or −80 °C before plunging into liquid nitrogen. Sperm equilibrated in 10% DMSO and cooled at a rate of 10 °C/min to a final temperature of −80 °C had the highest motility (91.1 ± 2.2%) and viability (92.7 ± 2.3%) after thawing. The fertilization rate of frozen-thawed sperm (72.4 ± 2.4%) was not different (P > 0.05) from that of fresh sperm (75.5 ± 2.4%). This study apparently represents the first reported attempt for cryopreservation of L. argentimaculatus sperm.     

Zwitterionic buffers preserve ram semen quality more efficiently than TRIS during storage at 15 °C

This study was designed to evaluate the effect of various buffers on the storage of ram semen at 15 °C. Second ejaculates from six adult males were collected using an artificial vagina and diluted in either MOPS, TRIS, TES, HEPES, citrate, or phosphate-based extenders. Semen samples were stored at 15 °C and the sperm motility and viability (membrane integrity) variables assessed after 0, 24 and 48 h intervals. Significantly higher progressive sperm motility rates were recorded at 0 h of storage, and higher motile and progressive sperm motility at 24 and 48 h, when zwitterionic-based extenders (MOPS, TES and HEPES) were used, compared to citrate, TRIS, and phosphate-based extenders—with the last group showing a drastic reduction in sperm motility during storage. The zwitterionic groups were also superior to the other treatments in terms of sperm velocity (straight line velocity, VSL; curvilinear velocity, VCL; average path velocity, VAP) at 0 h of storage, although at 24 and 48 h the differences were minimal in the CITRATE group—regarding all velocity variables, and in the TRIS group, regarding the VCL parameter. Sperm diluted in the TRIS-based extender showed a marked increase in the proportion of circular sperm trajectories (lower sperm linearity, LIN, and straightness, STR), and a decrease in the VAP. The reduction in the vigour of the sperm in the TRIS extender (measured by VCL) was less pronounced than in the other groups. At the same time, VSL was reduced, as more sperm moved in circles, and the amplitude of lateral head displacement (ALH) was also dramatically increased. The CITRATE diluent recorded intermediate results—between that of TRIS and the other treatment groups, regarding the variables related to the quality of sperm movement at 0 h storage. However, following CITRATE dilution, semen underwent a clear improvement after a period of 24 and 48 h, so that differences with the zwitterionic groups were attenuated or disappeared. Similarly, the CITRATE group obtained similar or higher viable sperm values, compared to zwitterionic buffers during storage. The TRIS, and particularly the PHOSPHATE diluents, recorded poorer sperm viability after 24 and 48 h of storage. It was concluded that zwitterion-based buffers may be an acceptable alternative for inclusion in the composition of diluents for chilled ram semen storage. On the other hand, TRIS may be seen as having caused drastic modifications of certain sperm kinematic parameters during storage at 15 °C.     

Effect of monensin on performance in growing ruminants reared under different environmental temperatures

To evaluate the effect of monensin on the performance of growing cattle under different environmental temperatures, 24 male calves (81.9 ± 7.7 kg mean weight and 100 days old) were distributed in a 2 × 2 factorial arrangement, contrasting 0 or 85 mg monensin/animal per day at 24.3 or 33.2 °C (environmental temperatures). Monensin supplementation increased weight gain (P=0.036), improved feed efficiency (P=0.040), increased ruminal concentrations of volatile fatty acids (VFA; P=0.003) and decreased the molar proportion of butyrate (P=0.034); all effects irrespective of environmental temperatures. A temperature-dependent monensin effect was detected on nitrogen retention (P=0.018) and N retained:N absorbed ratio (P=0.012). Animals fed monensin retained higher N amounts than those of the non-supplemented ones when the environmental temperature was 33.2 °C. Environmental temperature and monensin supplementation showed an interaction effect on urine N concentration (P=0.003). Temperature did not affect N excretion in monensin-fed animals, but increased N excretion in the non-supplemented ones. Monensin increased the crude protein (CP) digestibility (P=0.094) for animals at both temperatures. In conclusion, monensin changes the metabolism of the heat-stressed animals by increasing rumen VFA concentration, digestibility and protein retention, thus improving food use and weight gain.     

Changes in subpopulations of boar sperm defined according to viability and plasma and acrosome membrane status observed during storage at 15 degrees C

Four boar ejaculates were preserved for 42 d at 15 °C to examine the changes produced in the quality of sperm membranes according to their response to a combined short hypoosmotic swelling test (sHOST) plus viability test designated the sHV test. Every 1 or 2 d, a sample from each ejaculate preserved in long-term extender was subjected to sperm motility determination and the sHV test. Through simultaneous examination by phase contrast and fluorescence microscopy, three subpopulations of sperm were identified according to their response to sHOST challenge and their viability status. In the subpopulations scoring positive in the sHOST, a further four sperm subpopulations were defined according to their viability and acrosome status. All the sperm subpopulations differed in terms of changes in their proportions produced during the course of preservation and individual differences among ejaculates were detected in terms of relationships shown among subpopulations. The combined sHOST/viability test was able to identify sperm subpopulations with the strongest plasma and acrosome membranes as well as a subpopulation of sperm that had undergone a true acrosome reaction.     

Raffinose and hypotaurine improve the post-thawed Merino ram sperm parameters

The aim of this study was to determine the effects of raffinose and hypotaurine on sperm parameters after the freeze–thawing of Merino ram sperm. Totally 40 ejaculates of five Merino ram were used in the study. Semen samples, which were diluted with a Tris-based extender containing 10 mM raffinose, 5 mM hypotaurine, 5 mM raffinose +2.5 mM hypotaurine (H + R) and no antioxidant (control), were cooled to 5 °C and frozen in 0.25 ml French straws and stored in liquid nitrogen. Frozen straws were then thawed individually at 37 °C for 25 s in a water bath for evaluation.