Level and speciation of nickel in some forages in relation to spatial and temporal fluctuations

The present experimental work was conducted at different sites of district Bhakkar, a semiarid region of Pakistan, to assess whether the goats are suffering nickel deficiency or toxicity and what are the possible seasonal effects on the availability and translocation of nickel in food chain. A total of 27 forage and 320 goats according to four physiological stages [does (she goat), bucks (he goat), wether (castrated), juvenile (6 month)] were recruited for this study. To fulfill this objective, soil, forage, blood plasma, urine, and feces samples were collected in 4 seasons of the year at 2 sites and were analyzed by atomic absorption spectrophotometer for nickel concentration. Different indices BCF, EF, and PLI were also studied to check the metal transfer. The results showed that sites had significant (P < 0.05) effect on nickel concentration in soil, forage, and goats. On the other hand, season and site x season had nonsignificant (P > 0.05) effects on nickel level in soil and goats. The soil (0.68–0.71 mg kg⁻¹), forage (3.41–3.70 mg/kg), and blood (0.21–0.28 mg/l) level was lower than the permissible limits, while feces (0.57–1.34 mg/kg) and urine (0.35–1.32 mg/l) had enough concentration of nickel. Sources showed significant (P < 0.05) effects on Ni level in all stages of goats. All stages of goats except Wether (castrated) showed low level of nickel in blood. Most fluctuations in nickel concentration were observed in (S1) summer (low) and spring (S4) (high) season as a whole, while overall site 2 had high level of nickel than site 1. Thus, nickel showed deficiency in soil, forage, as well as in all stages of goats except wether goats. Nickel containing mineral mixtures are essential for does (she goat), bucks (he goat), and juveniles (6 months old), so application of Ni containing fertilizers to the soil and forage of that region and supplementation of Ni mineral mixture for grazing ruminants should be done.