This study was conducted to determine the effects of increasing dietary polyunsaturated fatty acids (PUFA) and antioxidants (Se and vitamin E) on spermatozoa morphology. At 24 weeks of age, Potchefstroom Koekoek cockerels (n = 60) were selected from the base population. Cockerels were randomly allocated into five dietary treatments with 12 cockerels per dietary treatment. The diets consisted of commercial layer diet (CL), commercial cockerel diet (CC), modified layer diet (ML), modified layer diet +PUFA (MLP), and modified layer +PUFA+ antioxidants (MLPA) diet. At 36 weeks of age, six cockerels with ≥ 75% sperm motility rate following analysis by Computer Aided Sperm Analysis (CASA) were selected from the base population in each dietary treatment group. Semen volume, sperm cells concentration and dead cells did not differ significantly among any of the groups. However, live and normal spermatozoa were significantly higher in the MLPA group. The bent mid-piece, bent mid-piece plus droplets, proximal droplets and distal droplets were significantly lower in the MLPA group. From this study it can be concluded that supplementation of polyunsaturated fatty acids and antioxidants may be of vital importance for normal morphology characteristics of spermatozoa in Potchefstroom Koekoek cockerels.
Spermatozoa integrity and maturity are important traits for reproductive potential of cockerels [
The impact of nutrition on sperm quality had been studied [
Spermatozoa are well equipped with an array of antioxidants against reactive oxygen species, but an imbalance between the production of reactive oxygen species and the available defence antioxidants results in oxidative stress [
The study was conducted at the Agricultural Research Council, Irene at the Poultry breeding section. Pure-bred Potchefstroom Koekoek chickens from the Irene flock were used. All birds were initially raised in floor pens up to 24 weeks of age. At 24 weeks of age, 60 cockerels were selected from the base population. Thereafter, cockerels were housed in individual cages of 47 cm × 32 cm × 61 cm. The selected chickens were examined for external parasites, particularly poultry lice and treated accordingly. Feathers of cockerels around the vent area were clipped.
At 36 weeks of age, 60 cockerels were randomly allocated into five dietary treatments with 12 cockerels per dietary treatment. The three treatment diets are presented in
At 36 weeks of age, each cockerel was trained for semen collection using the massage technique [
Composition % | ML | MLP | MLPA |
---|---|---|---|
Maize | 69.27 | 69.27 | 69.27 |
Soyabean full fat | 8.02 | 8.02 | 8.02 |
Soyabean 44 | 19.73 | 14.73 | 14.73 |
Fish oil | 0.0 | 5.0 | 5.0 |
L-lysine | 0.06 | 0.06 | 0.06 |
DL-methionine | 0.03 | 0.03 | 0.03 |
Vit-min premix1 | 0.15 | ||
Vit-min premix plus2 | 0.15 | ||
Vit-min premix plus AO3 | 0.15 | ||
Limestone | 0.9 | 0.9 | 0.9 |
Salt | 0.2 | 0.2 | 0.2 |
Mono Ca phosphate | 1.64 | 1.64 | 1.64 |
#LD = layer diet, CCD = commercial cockerel, MLD = modified layer diet, modified layer diet+PUFA diet, ML + P + AD = modified layer diet+PUFA+ antioxidants diet; 1Vitamin A 10,000,000 IU, vitamin D3 3,000,000 IU, vitamin E 20,000 Mg, vitamin K3 3000 Mg, folic acid 500 Mg, niacin 30,000 Mg, D-calpan 10,000 Mg, vitamin B1 2000 Mg, vitamin B2 5000 Mg, vitamin 6 3000 Mg, vitamin 12 20 Mg, biotin 60 Mg, antioxidant 3500 Mg, choline 300,000 Mg, iron 70,000 Mg, copper 8000 Mg, zinc 100,000 Mg, cobalt 500 Mg, manganese 120,000 Mg, iodine 1000 Mg, selenium 250 Mg, ronozyme NP 90,000 Mg; 2Vitamin A 10,000,000 IU, vitamin D3 3,000,000 IU, vitamin E 20,000 Mg, vitamin K3 3000 Mg, folic acid 500 Mg, niacin 30,000 Mg, D-calpan 10,000 Mg, vitamin B1 2000 Mg, vitamin B2 5000 Mg, vitamin 6 3000 Mg, vitamin 12 20 Mg, biotin 60 Mg, antioxidant 3500 Mg, choline 300,000 Mg, iron 70,000 Mg, copper 8000 Mg, zinc 100,000 Mg, cobalt 500 Mg, manganese 120,000 Mg, iodine 1000 Mg, selenium 250 Mg, ronozyme NP 90,000 Mg; 3Vitamin A 10,000,000 IU, vitamin D3 3,000,000 IU, vitamin E 200,000 Mg, vitamin K3 3000 Mg, folic acid 500 Mg, niacin 30,000 Mg, D-calpan 10,000 Mg, vitamin B1 2000 Mg, vitamin B2 5000 Mg, vitamin 6 3000 Mg, vitamin 12 20 Mg, biotin 60 Mg, antioxidant 3500 Mg, choline 300,000 Mg, iron 70,000 Mg, copper 8000 Mg, zinc 100,000 Mg, cobalt 500 Mg, manganese 120,000 Mg, iodine 1000 Mg, selenium 500 Mg, ronozyme NP 90,000 Mg.
Immediately after semen collection, the volume was determined using a graded-level collection tube. Sperm concentration of the semen samples was determined using a spectrophotometer.
Spermatozoa morphology was examined from smears stained with eosin/nigrosin [
The statistical program GenStat® [
The effects of polyunsaturated fatty acids and antioxidants on semen quality of Potchefstroom Koekoek cockerels are shown in
A summary of the values for the morphological characteristics of spermatozoa are presented in
Parameters | Dietary treatments | |||||
---|---|---|---|---|---|---|
CL | CC | ML | MLP | MLPA | p-value | |
Volume (ml) | 0.49 ± 0.03 | 0.50 ± 0.04 | 0.44 ± 0.04 | 0.38 ± 0.03 | 0.43 ± 0.04 | 0.479 |
Concentration (×109/ml) | 5.2 ± 317 | 5.0 ± 323 | 5.1 ± 328 | 5.1 ± 315 | 4.8 ± 327 | 0.816 |
Parameters (%) | Dietary treatments | ||||
---|---|---|---|---|---|
CL | CC | ML | MLP | MLPA | |
Live and normal | 71.5 ± 0.100d | 76.1 ± 0.101b | 74.1 ± 0.101c | 76.4 ± 0.101b | 82.5 ± 0.101a |
Dead | 7.75 ± 0.1 | 7.26 ± 0.1 | 7.36 ± 0.1 | 7.37 ± 0.1 | 6.72 ± 0.1 |
Bent mid-piece | 5.83 ± 0.17a | 4.67 ± 0.17b | 4.69 ± 0.17b | 4.04 ± 0.17b | 2.57 ± 0.17c |
Bent mid-piece plus droplets | 0.45 ± 0.97a | 0.18 ± 0.98b | 0.38 ± 0.97a | 0.20 ± 0.98b | 0.22 ± 0.97b |
Proximal droplets | 2.48 ± 0.36ab | 2.12 ± 0.36b | 2.53 ± 0.36a | 2.56 ± 0.36a | 0.67 ± 0.37c |
Distal droplets | 3.61 ± 0.25a | 2.82 ± 0.25b | 3.21 ± 0.25ab | 2.85 ± 0.25b | 1.09 ± 0.26c |
Coiled tailed | 2.62 ± 0.22a | 2.78 ± 0.22a | 1.82 ± 0.23bc | 1.49 ± 0.23c | 1.96 ± 0.23b |
Abnormal loose head | 2.01 ± 0.11b | 1.57 ± 0.118c | 2.12 ± 0.11b | 2.02 ± 0.11ab | 2.52 ± 0.11a |
Values are expressed as mean ± SEM. Rows with different letters are significantly different (p < 0.05).
number of live and normal spermatozoa of the cockerels fed MLPA diet was significantly higher than the other treatments. Cockerels fed CL diet presented the lowest percentage of live and normal spermatozoa. The percentage of dead spermatozoa did not differ significantly between the groups. The percentage of bent mid-piece was significantly lower in the cockerels fed MLPA diet than any other treatment. The percentage of bent mid-piece plus droplets of the cockerels fed CC, MLP and MLPA were lower than in the cockerels fed CL and ML. The percentage of proximal droplets and distal droplets were significantly lower in the cockerels fed MLPA compared to other treatments. The mean percentages of coiled tails were significantly lower on the treatment groups than in the groups on the commercial control diets (CL and CC).The cockerels fed MLPA diet had high percentage of abnormal loose head than the other treatments.
Supplementation of polyunsaturated fatty acids in the cockerel diet did not result in the improvement of semen volume and concentration. Several studies have shown that supplementation of dietary lipids in the diet does not alter the semen volume and semen concentration [
Results of the present study indicated a significant increase in the occurrence of live and normal spermatozoa in the cockerels fed the MLPA diet compared with other groups. Earlier studies showed that mature spermatozoa were enriched with polyunsaturated fatty acids in which the effects of oxidative stress were inevitable. Vitamin E is located in the spermatozoa where it performs its antioxidant role [
Selenium is also an essential trace element that plays an important role in a number of physiological processes including avian reproduction [
All the spermatozoa possess proximal droplets during the transit in the caput epididymis. It was reported that when spermatozoa underwent final maturational changes, proximal droplets migrated to the annular region (distal droplets) during transit in the cauda epididymis [
In order to produce normal spermatozoa, distal droplets are shed when spermatozoa are exposed to seminal plasma during ejaculation [
Zinc is concentrated in the tail region of the sperm [
The authors are grateful to the Poultry Breeding Section and their technical assistants for their help.