Evaluation of fresh and frozen-thawed semen of individual ganders by assessment of spermatozoa motility and morphology

Collection, Handling, and Preservation of Wild Bird Semen: Current Status, Challenges, and Perspectives

Semen preservation is a significant biotechnology used to safeguard the genetic material of birds, especially those with declining populations, through biobanking. However, there are limited reports on the successful chilling or cryopreservation of wild bird semen. In general, these techniques are not yet well-established for several species of wild birds and pose several challenges such as the need for bird handling and training, contamination of semen samples, low volume of semen collected, and inefficient preservation protocols. To address these challenges and improve post-thawing outcomes, new possibilities are being investigated, including alternative collection methods to traditional digital massage, the use of antioxidants and enzymes in the medium for chilling or freezing, storage methods using different straws from the usual pellet, and slower freezing rates. This review aims to discuss the various aspects of applying semen preservation in wild birds to create germplasm banks, highlighting the primary results obtained and the challenges that need to be addressed.

Changes in Sperm Morphology, Morphometry, and Motility from the Epididymis to the Vas Deferens in Rheas (Rhea americana, Linnaeus, 1758)

The objective was to characterize morphological, morphometric, and ultrastructural changes in rhea spermatozoa between the epididymis and the vas deferens. Sperm samples were collected from the reproductive tracts of seven adult individuals and evaluated for sperm characteristics using brightfield microscopy as well as ultrastructural features using scanning electron microscopy (SM). Mean sperm count tended to increase in the vas deferens (378.0 ± 135.0 × 10⁶) compared to the epididymis (201.0 ± 77.4 × 10⁶). Percentages of motile sperm grew from 37.0 ± 4.9% in the epididymis to 58.5 ± 7.7% in the vas deferens. The proportion of normal spermatozoa was 75.6 ± 1.8% and most common defects were bent tails (9.7 ± 0.9%). However, these proportions were not different between epididymis and vas deferens. SM analysis revealed further features of rhea spermatozoa. Normal rhea spermatozoa were threadlike with an acrosome (0.95 ± 0.0 µm), head (7.53 ± 0.01 µm), midpiece (2.08 ± 0.01 µm), and tail (30.7 ± 0.06 µm). Lengths of sperm acrosome, head, midpiece, and tail were longer in the vas deferens compared to the epididymis. Our findings suggest that rhea spermatozoa undergo a maturation process during the passage from the epididymis to the vas deferens.

Semen characteristics of ganders kept as genetic resources conservation program

The creation of genetic reserves of domesticated animal species and breeds almost become a necessity in the recent years, but there is a question what is the value of semen of males kept ex situ in vivo as gene conservation flocks. Presented studies assessed the response to semen collection by dorso-abdominal massage and the quantitative and qualitative semen characteristics of six goose breeds (Pomorska, Garbonosa, Kuban, Landes, Roman and Slovakia) covered by the genetic resources' protection program. Fourteen semen collection attempts were performed per male. In each breed there were ganders with low and high sensitivity to massage. The most positive reactions were stated in Pomorska ganders (67.9%), and the least in Kuban breed (52.60%). Individual male evaluation showed that only in three breeds (Pomorska, Garbonosa and Kuban) there were individuals showing 100% susceptibility to semen collection, in some breeds only 1-4 positive reactions (ending with ejaculation) were noted. Results obtained indicated breed and male effect on analyzed semen traits, with the exception of sperm motility. The highest number of live normal sperm (44.2% on average), sperm concentration (530 x10⁶ mL^-1 ), the highest Semen Quality Factor (92.9) and sperm motility (50.30%) were found in semen of Kuban ganders, while the lowest values of these traits (28.7%; 230 x10⁶ mL^-1 ; 11.4, respectively) in Slovakia ganders. The lowest sperm motility (38.3%) was observed in ganders of Roman breed, but comparing to the other breeds existing differences were not significant. Significant differences in sperm morphology between individual ganders were also observed.

The effects of glutathione supplementation on post-thawed Turkey semen quality and oxidative stress parameters and fertilization, and hatching potential

This study was conducted to investigate the effect of semen extenders enriched with glutathione (GSH) on in vitro quality parameters and fertility of post-thawed turkey. In experiment 1, pools of semen diluted in glucose-based extender containing 0.5, 1, and 2 mM of GSH were cryopreserved. During the next step, a different variable such as motility and motion parameters, plasma membrane integrity (PMI) and functionality (PMF), DNA integrity, lipid peroxidation (MDA), total antioxidant capacity (TAC), catalase (CAT), glutathione peroxidase (GPx) and superoxide dismutase (SOD) activity were determined in the post-thawed samples. In the second experiment, artificial insemination was used to evaluate the fertility and hatchability performances of the post-thawed semen. The results of the first experiment showed that the extenders supplemented with 2, 1 and 0.5 mM of GSH had higher levels (p ≤ 0.05) of motility and motion parameters, PMI, PMF, TAC, CAT and SOD activity and lower abnormal morphology, DNA damage, and lipid peroxidation respectively in comparison to the control group (only extender with semen). Notably, the second experiment showed a higher rate of fertility (p ≤ 0.05) in 2 mM of GSH compared to the control group. It can be concluded that adding 2, 1 and 0.5 mM of glutathione leads to an improvement in the survival of the post-thawed turkey, while 2 mM of GSH can increase the fertility strength of the turkey sperm; hence it can be used to improve fertility and hatchability performance.

Characteristics of semen collected from gander included in the genetic resources conservation program

Conservative breeding ex situ in vivo is one of the most popular methods of creating genetic reserves. Unfortunately, keeping animals in small closed populations leads to inbreeding which reduces their reproductive capacity. The aim of the study was to characterize the sperm quality of 6 genetic groups of geese (northern and southern breeds) kept in Poland for many generations as genetic reserve flocks. Each breed was represented by 10 randomly selected 1-yr-old ganders, semen was collected 14 times, individually from each male, and the number of positive reactions (ended with ejaculation), semen volume, sperm concentration, and morphology were assessed. The obtained results showed a significant difference between breeds and individuals of the same group, both in males’ reaction and semen quantitative and qualitative traits. From the northern breeds 193 ejaculates were obtained in total (i.e., 45.9% of all attempts), from the southern breeds 242 ejaculates (57.6%). The volume of single ejaculate varied from 0.01 mL (one drop allowing only histological smear and sperm morphology evaluation) to 0.65 mL; sperm concentration varied from 23.0 × 10⁶mL⁻¹ to 2376.0 × 10⁶mL⁻¹; the amount of total live sperm was at a similar level in all breeds (89.6%–97.7%), while live normal cells ranged between 15.2% and 67.9% depending on breed and individuals. When keeping the genetic reserves ex situ in vivo, attention should be paid to the quality of semen and males that are poor in this respect should be eliminated, in order not to lead to an excessive weakening of the reproductive capacity of the flocks covered by the genetic resources protection program.

The effects of natural mating and artificial insemination on reproductive traits of 1-and 2-year-old domestic Turkish geese

The aim of this study was to assess the sperm quality traits of 1- and 2-year-old ganders and the reproduction traits of 2-year-old domestic Turkish geese in natural mating (NM) and artificial insemination (AI) conditions. The study comprised 72 two-year-old females, 12 one-year-old, and 12 two-year-old ganders. Thirty-six female geese were mated naturally (18 with 1-year-old ganders, 18 with 2-year-old ganders); the remaining thirty-six were inseminated artificially (18 with 1-year-old ganders, 18 with 2-year-old ganders). Twenty-four ganders were separated into groups (12 for NM; 12 for AI). The male:female ratio was 1:3 for NM and AI groups. Egg production, broodiness, fertility and hatching traits were determined in female geese, sperm quality traits such as semen volume, sperm concentration, sperm quality factor (eSQF: ejaculated semen SQF; dSQF: diluted semen SQF), sperm motility, and sperm morphological traits in ganders. The insemination method and gander's age did not affect egg production, AI geese showed significantly more broodiness than NM groups as the breeding months progresses (p < 0.05). Fertility was higher in the groups containing 2-year-old ganders than in those 1-year-old ganders, and NM groups compared to AI (p < 0.05). The insemination method significantly affected semen volume, sperm concentration, eSQF, sperm motility, total live sperm, normal sperm, macro-cephalic sperm, and dead sperm percentages in ganders (p < 0.05).Managing females in the NM system with ganders was able to partially suppress the broodiness behavior, possibly due to synchronization of pair-bond behaviors. Greater fertility was achieved with 2-years-old AI ganders, which had lower dSQF compared to 1-year-old NM ganders. This is a good indication that only SQF is not sufficient to achieve sustainable-desired fertility, and sexual experience is also an important factor.

Effect of semen extenders and storage time on quality of Muscovy duck (Cairina moschata) drake semen during the entire reproductive season

Avian semen dilution with appropriate extender allows to prolong the fertilizing ability of sperm stored in vitro. In the present study, the impact of extenders and time of storage on morphology of Muscovy duck (Cairina moschata) drake semen were examined. Semen was collected twice a week, using male stimulation by a female method, from 12 adults (29 weeks old) drakes kept individually in cages, under controlled environmental conditions. Freshly collected, pooled ejaculates were divided into three part: neat undiluted sample, and diluted 1:1 with Schramm (SCH) or Watanabe (W) extender and stored at 4°C. Morphological examination of all samples was conducted after dilution and then, after 3 and 6 hr of storage. The storage of undiluted semen caused decrease (p ≤ .01) in live morphologically normal sperm, from 79.73% in the freshly collected ejaculates to 55.75% and to 12.12% after 3 and 6 hr of storage, respectively (average calculated for the entire reproductive season). In the semen diluted with Schramm's extender the adequate values attained 86.84, 79.65 and 61.66%, and using Watanabe extender 84.77, 83.58 and 75.25%, respectively. The period of semen storage and the type of extender caused significant (p ≤ 0,05; p ≤ 0,01) changes in sperm morphology. The longer period of storage contributed to the decrease in number of morphologically normal sperm, whereas their content in Watanabe extender after 3 and 6 hr of storage was higher (p ≤ .01) than in semen diluted in Schramm extender.

Spermiogenesis, Stages of Seminiferous Epithelium and Variations in Seminiferous Tubules during Active States of Spermatogenesis in Yangzhou Goose Ganders

The past three decades revolutionized the goose industry in the world. China holds the world's largest goose breeds stock by 95% of the global total. To optimize the goose industry and cope with ever increasing poultry meat and egg demands, there is a dire need to focus on reproduction, as most geese breeds exhibit poor reproductive performance. The present study was conducted with the aim to add a contribution in the goose industry and research by the histological visualizing step wise development of germ cells during spermatogenesis by microscopy and a histological technique. Yangzhou goose is a synthetic breed developed by using local goose germplasm resources of China. It is popular in the Chinese goose industry due to high productivity and adaptability. This research evaluated the steps of spermiogenesis and stages along with morphological changes in the seminiferous epithelium in Yangzhou goose ganders. For the assessment of various stages of the seminiferous epithelium cycle, testis sections were embedded in molten paraffin wax. The initial steps of spermiogenesis were depicted by changes in acrosomic granules, whereas further stages were identified by nuclear morphological changes. Ten steps of spermiogenesis and nine stages of seminiferous epithelium were identified. Four types of spermatogonia Ad, Ap1, Ap2 and B were recognized. The results depicted a clear variation in the diameter of seminiferous tubules (ST), epithelium height (EH), luminal tubular diameter (LD), number of seminiferous tubules per field and the Johnsen score. Microscopy indicated that the stages of seminiferous epithelium were similar to other birds and mammals and the ST diameter, EH, LD and Johnsen score are positively correlated while the number of seminiferous tubules per field is negatively correlated with the ST diameter, EH, LD and Johnsen score. Fertility in Yangzhou ganders can further be improved by visualizing the histological development of germs cells in testis tissues during spermatogenesis after onset of breeding season and maturity. Our results suggest that Yangzhou ganders reach complete sexual maturity at 227 days of age.

Association of antioxidant defense system with semen attributes vis a vis fertility in exotic and indigenous chicken breeds

The present study was designed to ascertain the association of antioxidant defense system with semen attributes and fertility in RIR (Rhode Island Red), PR (Punjab Red), RIR x local cross, Aseel and Kadaknath breeds. Based on sperm attributes, roosters of each breed were divided into two group i.e. G-I (exhibiting >50% sperm attributes) and G-II (exhibiting <50% sperm attributes). Motility, viability, membrane-, acrosome-, DNA-integrity and fertility differed significantly (p < 0.05) among the breeds, representing maximum in PR roosters and least in Aseel roosters. Values of sperm attributes and fertility rate were also significantly (p < 0.05) higher in G-I compared to G-II roosters in exotic as well as indigenous breeds. MDA content differed significantly (p < 0.05) in spermatozoa of five breeds. It indicated a least oxidant stress in PR and highest in Aseel. MDA concentration was significantly (P < 0.05) higher in G-II (28.36 ± 2.40-96.0 ± 6.4) than G-I (13.65 ± 1.81-52.22 ± 6.4) roosters in all breeds. Antioxidant enzyme activity varied significantly (p < 0.05) among the breeds and groups within the breeds. Significantly (p < 0.05) higher activity of four enzymes was evident in G-II as compared to G-I roosters irrespective of the breed. A moderate to strong negative correlation was perceived among LPO, SOD, GPX, catalase, GRE and sperm attributes/fertility rate. A moderate to strong positive correlation (0.21-0.92) among LPO and antioxidant enzymes revealed that with the increase in LPO, antioxidant enzymes increase too and vice versa in all breeds. Likewise, positive correlation between sperm attributes and fertility revealed that higher sperm attributes contribute to the high fertility of roosters. This is one of the first reports on complete set of antioxidant enzymes and oxidative stress in relation to sperm attributes and fertility in different five chicken breeds. A complete antioxidant enzyme system seems to modulate the oxidative stress, sperm attributes and fertility. It may be possible to use LPO as a fertility marker to select the roosters for breeding purpose in the chicken breeds.

Simple and effective methods of freezing capercaillie (Tetrao urogallus L.) semen

A continuous decline in the number and range of capercaillie (Tetrao urogallus L.) in many European countries can be observed, mostly due to habitat destruction by human activity, unecological forestry management, and increased density of natural predators. Ex situ in vitro gene banks provide a unique opportunity to preserve the genetic material for future generations. Simple and effective cryopreservation methods for capercaillie semen are discussed. Semen was collected from seven males kept in the Capercaillie Breeding Centre at Forestry Wisła in Poland. Within five minutes after collection, ejaculates were diluted with EK diluent, then divided into two parts, and subjected to two freezing procedures: in pellets and in straws. In fresh semen, ejaculate clearness, viscosity, color and volume, as well as sperm concentration, motility and morphology, were evaluated, while in frozen-thawed semen only motility and morphology of sperm were determined. Fertilizing ability of thawed semen was examined for samples frozen in straws. Significant (P<0.05) differences between individual males were found in relation to the majority of fresh semen traits: ejaculate volume averaged 102.1 µL (varying from 49.0 to 205.0); average sperm concentration was 632.5 x10⁶ mL^-1 (178.8–1257.1); percentage of live normal cells varied from 39.2 to 70.3% (58.7% on an average); percentage of motile cells ranged from 76.0 to 85.7%) and motility parameters were male dependent, as well. Both cryopreservation methods had a negative effect on morphology and motility of frozen-thawed semen; however, the straw method yielded 60.7% and the pellet method 42.5% of live cells in total in thawed semen (P<0.05), while the number of live normal (intact) cells was similar (22.4 and 22.2%, respectively). Egg fertility varied between 77.8 and 91.7% (average 84.4%). Both freezing procedures seem to be effective in obtaining acceptable viability and high fertilizing potency of thawed sperm and can be used to create a gene bank of capercaillie semen.

A diagnostic method for gander selection in Zi geese (Anser cygnoides L.) and Rhin geese (Anser anser L.) using massage reaction and semen quality

The objective of this study was to score reactions to artificial semen collection procedures and to develop an efficient method for gander selection in two original geese breeds. One-hundred and three Zi geese and 110 Rhin geese were used. Gander reaction scores to massage and semen quality parameters were investigated in 10 Zi and 10 Rhin ganders during a complete reproductive season. The relationships between average gander massage reaction score and semen quality were evaluated. After natural mating, egg fertility comparison between Zi ganders selected by massage reaction scores and those not subjected to selection were investigated. Ganders exhibited large variations in artificial semen collection and semen characteristics between breeds. Only 30.1% (31/103) of Zi geese and 46.3% (51/110) of Rhin geese had stable positive massage reactions with semen ejaculation (P < 0.05). Average massage reaction score, ejaculate volume, spermatozoa concentration, sperm motility and semen quality factor for single ejaculate were significantly higher in Zi than in Rhin geese. There was a high correlation between average massage reaction score and semen volume, being 0.87 for Zi geese (P < 0.05) and 0.82 for Rhin (P < 0.05), and this correlation enabled pre-selection of ganders at the beginning of the breeding season. Reproductive efficiency could be improved with massage-selected ganders in natural breeding flocks. Examination of gander massage reaction scores combined with laboratory assessment of semen quality early in the breeding season is a feasible method for predicting fertilising capability of ganders.

Effect of dietary selenium and vitamin E on ganders' response to semen collection and ejaculate characteristics

Compared to other domestic bird species, geese exhibit the lowest reproductive efficiency (poor semen quality, low egg production, and poor fertility and hatchability rates). From an economic perspective, it is a necessity of improve these reproductive traits. Studies have demonstrated that the essential trace element-selenium-plays key roles in testicular development and the maintenance of spermatogenesis. The aim of the present study was to determine the effect of feed supplementation with organic selenium and vitamin E on ganders' response to manual semen collection and semen quality. Sixteen 3-year-old White Koluda ganders were randomly divided into two groups. The control group was provided commercial feed while the experimental group was provided with the same commercial feed supplemented with selenium (0.3 mg/kg) and vitamin E (100 mg/kg). The response of individual ganders from both groups to manual semen collection and the quality of the semen collected were evaluated. The supplements increased (P ≤ 0.05) the frequency and decreased the time interval of a complete ejaculatory response of the ganders to manual semen collections (82.7 % supplement vs. 73.5 % control). Males from the supplemented group had significantly higher (P ≤ 0.01; P ≤ 0.05) ejaculate volumes, sperm concentrations, and percentages of viable sperm and lower percentages of immature sperm (spermatids). Lipids peroxidation, expressed in terms of the malondialdehyde concentration, was lower (P ≤ 0.01) in semen of the supplemented group (0.172 nmol/50 × 10(6)) as compared to the controls (0.320 nmol/50 × 10(6)). Moreover, the duration of the reproductive period of the ganders in the experimental group was 1 week longer. The results show that supplemental dietary selenium and vitamin E improved both the ganders' response to manual semen collection and semen quality. We conclude that such feed supplementation could lead to greater economic benefits through increased reproductive efficiency within the goose production industry.

Effect of different managerial systems on productive and reproductive traits, blood plasma hormones and serum biochemical constituents of geese

A flock of 117, 10-month-old Egyptian geese consisting of 90 females and 27 males were utilized in this investigation. Birds were randomly divided into three equal groups, each made up of three replicates of 10 females and 3 males each. The first group was kept under a pasture system (PS) and allowed to swim in water ducts during the daytime (PS) and kept inside the house during the night. The second group of birds were kept in confinement in a house and fed ad libitum on a commercial feed (intensive system (IS)). Birds in the third group (semi-intensive system (SIS)) were released from the house for 6 h a day and given access to the pasture and water ducts. Each group was housed in three pens (replicates) in the SIS. They were given ad libitum access to the commercial feed when in the house. Each pen measured (2 × 3 m2). Natural mating was practiced during the period from November to the end of May. BW of geese under ISS was significantly (P ⩽ 0.05) higher than those under PS and SIS. Egg number, weight and mass of geese in the SIS system were significantly (P ⩽ 0.05) greater than those of geese in the PS and IS systems. Fertility and hatchability percentages were significantly (P ⩽ 0.05) greater in the PS (84.2% and 88.6%) than in the IS (77.5% and 82.8%) and SIS systems (80.7% and 85.5%). Shell weight and thickness were significantly (P ⩽ 0.05) better in the IS and SIS systems than in the PS system. Geese in the PS and SIS systems exhibited significantly higher plasma estradiol-17 and progesterone than those in the IS. Testosterone was significantly higher in IS than in the other systems. Semen quality factor was significantly higher in the PS and SIS systems than in the IS system. Carcass weight was significantly greater in IS and SIS geese than in PS geese, but the PS system resulted in a decreased percentage skin, abdominal fat and liver. Total amount of meat produced per geese was significantly greater in the SIS than in the IS system and greater in the IS than in the PS system.