Male health & its effect on hatchability

Achieving the best fertility is the only goal for successful running of any breeder operation. Advanced genetic selection in broiler breeding has led to tremendous improvements in progeny performance. Body weight gain achievement in modern broiler breeders is swifter than the past hence male management is a crucial aspect to obtain good quality and quantity of semen.

Due to some unforeseen events if there is heavy mortality in males, maintaining the fertility of the flock is a difficult task and here the role of the male management comes in picture.

Due to the continuous milking i.e. once in 3 days the males are under tremendous pressure and due to handling they may land in development of locomotory issues like lameness and the ability of these males to maintain semen production with good quality and quantity tends to decline which paves way for spiking of the males.

It is defined as union of the sperm from the male with the egg or ovum of the female. Although several sperms penetrate the cell wall of egg, only the nucleus of one sperm unites with the nucleus of the egg in the fertilization process.

The other sperms are called as supernumerary sperms and disappear between 4-5 hours after fertilization.

Hen's egg is normally fertilized in the infundibulum within 15 minutes after it is released from the ovary. Normal, active spermatozoa are found in the infundibulum of the female up to 14 days after insemination & they are located in the crypts or gland ducts in the mucus lining of the infundibulum as many as 50-80 sperms in one duct.

Sperm inseminated in the rear end of the oviduct may reach the infundibulum in less than 30 minutes but when hard shelled egg was present in the oviduct, sperms were retained in the inseminated area until egg was laid and upon oviposition, rapid progress of the sperms towards the infundibulum was observed (Mimura 1939). Unlike mammals the reproductive system of chicken male is entirely located inside the body.

Contrary to the mammals, chicken sperms are viable at body temperature.

There is one pair of testes located just above the kidneys. The cranial pole of the testes lies close to ventral border of the lungs, while caudal poles lie cranio-ventral to the cranial divisions of the Kidneys (Nickel et. Al. 1977). There are no known accessory sex glands in poultry.

There are two bean-shaped testicles inside the body cavity which produce both spermatozoa and male hormones. Left testes is slightly larger than the right one and the basis for this asymmetry lies in uneven migration of primordial germ cells to the left and right side of the body during embryogenesis.

Testes are highly vascularized and change in size and position depends on whether the male is sexually active or not.

The age of sexual maturity in males is directly related to their lighting programme. However, spermatozoa production does not usually begin until the males are at least 24 weeks of age. From the testicles the spermatozoa move to the epididymis. Testes are partially surrounded by the posterior thoracic and abdominal air sac membranes. Air sacs may serve to cool the testes during spermatogenesis.

The testes are pale yellow but occasionally a pigmented or partially pigmented testicle is observed. Testes of Leghorn are smaller than meat type birds.

The combined weight of testes comprises of about 1% of the total weight of the adult male bird. Large testes not only produce more sperms overall, but apparently produce more sperms per ejaculate (Moller 1988).

The bulk of the testes are composed of thousands of seminiferous tubules.

It is in these tubules that the germ cells are changed into sperms by the process of spermatogenesis.

The sperms are found in clusters with the tails projecting into the centres of the tubules and the heads attached to sertoli or nurse cells.

In the male fowl the male sex hormone is secreted by seminiferous tubules.

Epididymis is small and rudimentary in comparison to other farm animals. When sperms mature, the heads get detached and the sperms pass through the tubules into the excurrent ducts of epididymis.

After the sperm pass through the ducts of epididymis they enter the vas deferens.

Each vas deferens extends from the epididymis to the cloaca and is situated near the middle of the back close to the vertebral column.

Each vas deferens extends from the epididymis to the cloaca and is situated near the middle of the back close to the vertebral column.

As the ducts continue backwards they become larger in diameter until at the point where they enter the wall of the cloaca. Semen is temporarily stored in this enlarged or bulbous portion.

The copulatory apparatus of the male consists of two papillae and a rudimentary copulatory organ. The sperm ducts enter the wall of the cloaca and terminate in two small, conical-shaped papillae. Each papilla has a hole through which semen is emitted during copulation.

Male chickens, which possess only a rudimentary phallic nub, pump their sperm into females using a 'cloacal kiss' a move that presses together the male and female cloacas, openings used for waste excretion and copulation.

Avian sperms differ from mammalian sperms in having slender, cylindrical heads which are equipped anteriorly with a distinct, sharp pointed structure called acrosomes.

There are globules of fat and fatty acid material in the sperm head and these globules might serve as stored food material.

Sertoli cells are regulated by FSH from the pituitary gland and testosterone from the Leydig cells. Sertoli cells are unable to significantly synthesize steroids de novo, per se, but promote interconversion of steroids e.g. progesterone and androstenedione to testerone and reduced 5 α-androgens.

Androgen binding proteins (ABP), inhibin and activin are endocrine regulators of FSH production and of testicular steroidogenesis and spermatogenesis.

The phagocytic ability of the sertoli cell is well known and these have been observed to remove residual bodies in the roosters (Cooksey and Rothwell 1973).

One of the most important functions of sertoli cells is the establishment of the most durable component of the blood testis barrier, which creates two fluid components within the seminiferous epithelium.

It has important protective role in safeguarding the germ line from noxious influences originating both from within and external to the individual.

Sertoli cell-Leyding cell interactions also exist, in which both cells influence each other with regard to setriodogenic activities, as well as inhibin and activin secretions.

Vitamin A is required for fertility and normal spermatogenesis & deficient males produce fewer sperms. Vitamin E protects the sperm's cell membrane, tail from damage due to lipid peroxidation and improves sperm motility. Vitamin E supplementation in males resulted in increased fertility rates.

Antioxidants such as Vitamin E and C, carotenoids and carnitine have been found beneficial in restoring a balance between Reactive Oxygen Species generation and scavenging activities.

Supplementation of dietary Vitamin C increased semen volume and increased sperm concentration per ejaculate. Biotin can enhance the sperm motility and prolong the survival of frozen-thawed semen samples.

B vitamins also play an important role in maintaining male health indirectly by improving metabolic process in body.

Selenium helps in the maintenance of reproductive functions especially sperm concentration, motility and sperm capacity in males. Supplementation significantly increases FSH, LH Testosterone and Glutathione levels.

Zinc has an important role in male health, plays a role in epithelial integrity, sperm quality, fertilization, regulative role incapacitation and acrosome reaction. Zinc can't be stored in the body and thus regular dietary intake is required. Zn deficiency impedes spermatogenesis and has a negative effect on serum testosterone concentration.

Chromium is a potent hypocholesterolemic and antioxidant agent. Beneficial effects of Chromium have been linked with improvements in metabolism and immune system. Chromium supplementation improved semen quality (ejaculate volume, motility & live sperm %), reproductive organ weights as well as fertility and hatchability %. The improvement in semen quality may be attributed to the antioxidant activity of chromium which maintained the integrity of cell membrane and reduced damage due to oxidants. There is reduction of malondialdehyde concentration which indicates integrity of sperm membranes and their fertilizing ability. Deficiency of Manganese will lead to testicular degeneration in males.

COS are the enzymatic or chemical hydrolysis products of chitosan or chitin and commonly used to increase libido and reduce plasma lipid levels in males; they have low molecular weight, good solubility, low viscosity

COS has been shown to reduce the establishment of pathogens in the intestine and improve immune function. It has also been shown to reduce triglyceride levels.

EFA supplementation, especially ω-3 and ω-6, helps in improving fertility, sperm concentration, semen quality and quantity. Higher ω-3 fatty acid proportions in the phospholipids of sperm improve spermatozoa traits like membrane resistance to peroxidative damage, increased fertility and hatchability, live sperm, total sperm count and other sperm quality factors.

Dietary essential oils supplementation had a significant effect on the semen glucose content, alanine aminotransferase activity, semen protein content. Sperm motility, progressive motility, membrane functionality, viability were significantly improved; the testosterone concentration increased; and a higher fertility rate was noted. The spermatogonial development and germ cell layers and GnRH, LH, FSH, Testosterone hormone levels increased, they regulate the expression of hormone receptors and Steroidogenic Acute Regulator Protein (STAR).

A number of phytogenic compounds are used from long time to improve male health.

Asphaltum (Shilajit) an established aphrodisiac, composed of at least 85 minerals in the ionic form, includes triterpenes and aromatic carboxylic acids. Other ingredients identified are gums, resins, aluminium, calcium, potassium, nitrogen, silica, vegetable matter, magnesium, sulphur, iron, chloride, phosphorus, iodine, glycosides, tannic acid, benzoic acid and a number of vitamins and enzymes.

Its usage may lead to increase in semen volume, number of sperms, motility percentage, mass activity and decrease in pH and dead % of sperms. Asphaltum increases sensitization of the male which helps in increase in production of testosterone and express libido, further it will increase the blood supply to the gonads and has antistress activity as well.

Asparagus: improves fertility and hatchability as it is an organic source of vitamin A, C and B vitamins.

Ashwagandha (Withania somnifera) is an aphrodisiac commonly used in improving male health and helps in increasing semen volume, sperm count & sperm motility, it is a very important remedy to treat oligospermia.

Elephant creeper roots are bitter & astringent sweet in taste with a cool potency. It has acrid, emollient, diuretic, anti-inflammatory qualities and is especially known for its rejuvenating, intellect promoting, brain and nervine tonic actions, very helpful in improving male health.

Other phytogenics used in improving male health are Zinger, horny goat weed (Corozza 2014), Sesame, Maca, Maltese mashroom, Yohimbine (Clark JT 1984), Velvet bean, Pipli, Gokhru (Salman & Adesokan 2008; Shittu et al. 2008; Khaki et al. 2009)

Conclusion:

Maintaining male health in the modern breeders is a herculean task due to changes in the genetics.

Male health should ideally be maintained on balanced composition of herbal and synthetic ingredients which may lead to improved performance if maintained only on the either herbal or synthetic ingredients lonely, it won't express optimum response as per as fertility and hatchability is concerned.

Routine observation of the flock (lameness, ear infection, comb and wattles appearance, feathering pattern, feeding pattern and gait), daily grading of the males, providing skimmed milk powder, germinated legumes and supplementation of balanced nutrition is key in improving male health.

During the hot summer months, male health related supplements should be used for extended period (for 15-20 days against 10 days a month in other seasons) this will help in maintaining desired fertility and hatchability.

The cost of spiking of male can be saved by practicing the said recommendations.

No supplement is alternative for good management, preventive vaccination, biosecurity, nutrition and health care even in today's advanced breeder genetics era.