Effect of preservation methods of oil palm sap (Elaeis guineensis) on the reproductive indices of male wistar rats

Abstract

Thirty male Wistar rats, split into five groups of six rats each, were administered different forms of oil palm tree (Elaeis guineensis) sap samples by gavage based on 1.5% of their weekly body weights. Group 1 which served as control received only water, group 2 received pasteurized palm sap (PPS), group 3 received market palm wine (MPW), group 4 received frozen palm sap (FPS), whereas group 5 received fresh palm sap (FrPS). Chemical composition of the sap samples was determined. Normal feed and water were fed ad libitum. After 2 months of treatment, each male rat group was allowed 7 days to mate with six female Wistar rats. Thereafter, blood and epididymal samples were collected for testosterone assay and sperm count, respectively, before they were humanely sacrificed and testicular tissues taken for testicular histology. Litter weight and size of the pups produced by the females of each group were determined at birth. The sap samples contained carbohydrate (0.01-11.71%), protein (1.56-1.95%), ash (0.22-0.35%), moisture (92.55-98.24%), and alcohol (0.26-3.50%). PPS-treated rat group had significantly (P<.05) decreased sperm count (42.60±23.64×10(6)), abnormal increase in testosterone level, and necrosis in the histology of the testes with reduced spermatogenetic activity, compared with other treatment groups. The female rats crossed with male rats fed on FrPS or FPS produced the highest number of pups followed by the control group. This study demonstrated that the intake of FrPS improved fertility in male animals, but its administration for a long period led to necrotic changes in the testes, whereas pasteurization of palm sap, impacted negatively on the reproductive indices of male animals.

Keywords: fertility; freezing; pasteurization; testis; testosterone.

FIG. 1.

Alcohol content of oil palm sap products.

FIG. 2.

Histology of rat groups' testes after 2 months of treatment (×400). (A) Group 1–Male Wister rats treated with normal feed+water. The spermatogonia (G) and seminiferous epithelia (S) are active in spermatogenesis with spermiation occurring in seminiferous lumen (L). (B) Group 2–Male Wister rats treated with normal feed+water+pasteurized palm sap (PPS). (C) Group 3–Male Wister rats treated with normal feed+water+market palm wine (MPW). (D) Group 4–Male Wister rats treated with normal feed+water+frozen palm sap (FPS). (E) Group 4–Male Wister rats treated with normal feed+water+frozen palm sap (FPS) (advanced stage of necrosis). (F) Group 5–Male Wister rats treated with normal feed+water+freshly tapped palm sap (FrPS). N=Invisible Leydig cells in the interstitial spaces. Color images available online at www.liebertpub.com/jmf