Effect of supplementation of valine to chicken extender on sperm cryoresistance and post-thaw fertilization capacity.

Recent reports showed a positive correlation between frozen-thawed rooster sperm DNA integrity and the concentrations of valine in seminal plasma. The present study evaluated the effect of supplementing valine to semen extender for freezing sperm of 2 endangered local Spanish chicken breeds with different sperm cryoresistance: Red Villafranquina (VF) showing low sperm DNA integrity after cryopreservation and Quail Castellana that shows higher DNA integrity. One pool of semen per breed was obtained twice a week for 10 wk (n = 40, 20 per breed). Each pool was divided into 2 fractions. One of these fractions was frozen in presence of valine as additive in the extender (concentration 10 mmol), whereas the other was used as control. The evaluation of the samples before and after freezing-thawing included motility (CASA-Mot system), viability (propidium iodide and SYBR-14), DNA integrity (terminal deoxynucleotidyl transferase dUTP nick end labeling), and fertility rate (percentage of eggs with blastoderm development after artificial insemination). Supplementation of valine increased several motility variables of fresh semen. In VF breed, valine increased percentage of progressive motile sperm (P = 0.025), curvilinear velocity (P = 0.033), straight-line velocity (P = 0.040), and average path velocity (P = 0.033), whereas progressive motile sperm (P = 0.019), curvilinear velocity (P = 0.006), straight-line velocity (P = 0.003) and average path velocity (P = 0.004) were improved in the Quail Castellana breed. Valine addition increased the DNA integrity of cryopreserved semen (decreased post-thaw DNA fragmentation) in both breeds, with a significant effect (P = 0.002) in VF (36.3% VF-control vs 31%VF-valine). As expected, Quail Castellana cryopreserved sperm control showed higher fertility rate (34.4% ± 12.1) than VF cryopreserved sperm control (16.1% + 6.2). Supplementing valine to the freezing extender doubled (P = 0.026) the fertility rate of VF (32.6% ± 12.2) compared with the control (16.1% + 6.2). In conclusion, supplementation of valine to chicken freezing extenders shows a positive effect on DNA fragmentation and fertilizing ability of frozen-thawed sperm, with a better response in a breed considered as the lowest freezer in our conservatory.

Can by-products replace conventional ingredients in concentrate of dairy goat diet?

Intensive dairy goat production in the Mediterranean basin is based on imported conventional ingredients to be included in concentrates. Fourteen Murciano-Granadina goats in the middle of the third lactation were allocated into 2 groups of 7 animals each fed, respectively, a control diet based on alfalfa hay and concentrate in a 40:60 ratio, and a diet in which the concentrate included tomato fruits, citrus pulp, brewer's grain and brewer's yeast (T100CBY) to study the effect of diet on nutrient utilization, ruminal fermentation, purine derivatives excretion in urine, milk yield and composition, and methane emissions. No effect of the diet on total dry matter intake was observed. Digestibility of neutral detergent fiber and acid detergent fiber were higher for T100CBY compared with the control diet. The N in feces and urine was lower and balance and retained N were higher in animals fed T100CBY than the control diet. Milk protein N and energy were similar for both diets. Metabolizable energy per energy intake and metabolizable energy per digestible energy were higher and energy in methane was lower with diet T100CBY than with the control. Milk yield and composition were not affected by diet, with the exception of protein, casein, and total solids, which were higher for diet T100CBY than the control. Diet T100CBY promoted less saturated fatty acids and higher mono- and polyunsaturated fatty acids in milk than the control diet. Diet T100CBY produced less methane and NH3 concentration in the rumen, higher propionate, and a lower acetate-to-propionate ratio without an effect on the volatile fatty acid concentration. The concentrate with by-products did not affect urinary excretion of total purine derivatives, reduced feeding costs, and increased profit margin by 14 and 16% compared with the control. The mixture of tomato fruits, citrus pulp, brewer's grain, and brewer's yeast could replace 47% of conventional ingredients (corn, wheat bran, sunflower meal, and soy flour) in the concentrate of the dairy goat diet, reducing feeding cost and methane production, leading to a healthier fatty acids profile in milk without compromising nutrient utilization or milk yield.

Dynamics of sperm DNA fragmentation in the swine: ejaculate and temperature effects.

The dynamics of sperm DNA fragmentation was examined in 16 boar ejaculates using the sperm chromatin dispersion (SCD) test and a two-tail comet assay. The net sperm rich fraction was preserved at two different temperatures (Trial 1: 15 degrees C, n=10; Trial 2: 37 degrees C, n=6) and sub-samples were taken every day until a sperm motility of zero. Significant differences in the dynamics of DNA fragmentation were observed among the different ejaculates and also according to the storage temperature. After analyzing the dynamic response of the sperm DNA damage, when the sperm samples are incubated at 15 or 37 degrees C, each ejaculate could be classified and a considerable variation among individuals for an increase in DNA damage was observed. Thus, while in some ejaculates no rise in DNA fragmentation was observed, in others, the sperm DNA fragmentation process was triggered during the initial days of the experiment. In general, sperm incubation at 37 degrees C diminished sperm DNA quality. The two-tail comet assay indicated that at time zero existing DNA damage mainly consisted of double stranded DNA breakage. During storage, DNA damage affected one of the DNA strands until a second wave of DNA damage, in which there was both single and double stranded DNA damage.

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 42d at 15 degrees 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 2d, 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.

Sperm DNA fragmentation in a random sample of the Spanish boar livestock.

A collection of 180 chilled boar semen samples, randomly chosen from stocks currently used for routine characterization of standard seminal quality, were studied for DNA fragmentation status using the sperm chromatin dispersion test and the DNA fragmentation index (DFI: percent of abnormal cell versus normal cells for DNA fragmentation) was determined. Values for sperm motility, acrosome status, coiled tails and abnormal head morphology, including presence and position of cytoplasmic droplets were also obtained. The DFI in the whole sample presented a wide range of variation with values oscillating between practically 0% and 47.95% and do not fit to a normal distribution. The most frequent classes (83.3%) presented a DFI lower than a 5%. Significant correlations between sperm DNA fragmentation and sperm motility, acrosome status, frequency of distal droplets, coiled tails and abnormal head morphology, were not observed. However, the presence of proximal cytoplasmic droplets showed a significant correlation with the level of DNA fragmentation observed in the ejaculated spermatozoa.

Bayes factor analysis for the genetic background of physiological and vitality variables of F2 Iberian x Meishan newborn piglets.

The Bayes factor (BF) procedure was applied to examine the additive genetic component of several physiological and vitality variables for newborn pigs. Nine variables were studied: heart rate, arterial oxygen saturation, rectal temperature (all at birth and 60 min later), birth weight, interval between birth and first teats contact, and interval between birth and first colostrum intake. The available numbers of data ranged from 288 (heart rate at 60 min) to 839 records (birth weight) from F(2) Iberian x Meishan newborn pigs. We compared a model with zero heritability (nonheritable) with the one where the additive genetic background was included. The BF was used to discriminate between both candidate models. Very strong evidence of genetic background was detected for heart rate 60 min after birth (BF = 48.90), and strong evidence was detected for rectal temperature at birth (BF = 13.82). Posterior modes (means) of heritabilities were 0.29 (0.32) and 0.40 (0.39), respectively. In addition, substantial evidence of absence of genetic background was detected for arterial oxygen saturation at birth.

A short hypoosmotic swelling test for the prediction of boar sperm fertility.

This study was designed to explore the relationship between the ejaculate response to a hypoosmotic swelling test (HOST) and in vivo fertility in a group of 38 boars The hypoosmotic test used was a modification of the HOST that involves a shorter incubation time (5 vs 120 min) and lower osmotic pressure (75 vs 150 mOsm/kg). Ejaculates containing less than 20% abnormal spermatozoa were selected and checked for percentage of motility, percentage of normal acrosomes, percentage of short ORT and percentage of cells showing positive short HOST (sHOST) results Two hundred eightyeight sows were inseminated to obtain in vivo fertility and prolificacy data. No differences were shown between technicians in the sHOST results obtained. Significant differences were recorded between boars in sHOST results (p < 0.002). Only the sHOST result presented a significant correlation with in vivo fertility (r = 0.43, p < 0.01). Short HOST data significantly improved fertility prediction of routine semen analysis tests. Unlike motility and acrosomal status, sHOST values showed a significant decrease when fresh ejaculates (37 degrees C) were stored for 24 h at 15 degrees C, indicating possible damage due to cold shock.