Browsing by Author "Vulla, Kelvin"

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Climate-smart aquaculture in Tanzania: Assessment of transitional and heavy metals concentrations in a commonly used local feed ingredient for Tilapia farming
(IJASRE, 2023-11) Vulla, Kelvin; Mmanda, Francis; Makule, Edna
A study conducted from January through May 2023 to assess the concentrations of heavy and transitional metals in a commonly used local feed ingredient in a farmed Nile tilapia diet (Oreochromis niloticus) in Tanzania. Eleven fish feed ingredients such as, sunflower seed cake (SFSC), wheat pollard (WP), maize bran (MB), fish meal (FM), freshwater shrimp (FWS), cattle blood meal (CBM), bone meal (BM), soya bean meal (SBM), and rice bran (RB), brewers’ spent grain (BSG) and Taro leaves (Colocasia esculenta; TL) were randomly sampled from feed manufacturers, animal feeds’ centers and other animal feeds suppliers in Arusha and Dar es Salaam region for inclusion in this study. Heavy metals and transition metals in feed ingredients were analyzed using the Energy- Dispersive X-rays Fluorescence (XRF) (Xla Pro-Spectrometer/German) at the Tanzania Atomic Energy Commission (TAEC) laboratory. The results showed that most of the fish-feed ingredients used in this study comply with the maximum allowable concentrations in Nile tilapia diets-according to the Tanzania bureau of standards and the European commission. However, the results showed that, the concentrations of reported metals (As, Pb, Cd, Hg, Co, Cu, Mo, Mn, Ni, Ag, V, Cr, Fe and Zn) varied significantly (p < 0.05 ) in most of the analyzed local feed ingredients collected in Tanzania. The study has paved the way for other researchers to further assess more feed ingredients used not only on heavy metals but other potential contaminants in feeds to ensure sustainable fish farming in Tanzania.
Polyphosphates: Essential bioenergetic reservoirs and their role as critical nutrient depleters in biological systems
(Scientific Research Archives, 2025) Vulla, Kelvin; Francis, Beatrice; Komba, Richard; Janes, Zabron
Polyphosphates are linear polymers of inorganic phosphate that play a pivotal role in cellular bioenergetics and metabolism across a wide range of organisms. This review article explores the multifaceted functions of polyphosphates as essential bioenergetic reservoirs, highlighting their ability to store and release energy, thereby facilitating various biochemical processes. We discuss the synthesis and degradation pathways of polyphosphates, their influence on ATP metabolism, and their regulatory roles in cellular signaling and stress responses. Additionally, we examine how polyphosphates act as critical nutrient depleters in biological systems, impacting phosphate homeostasis. The interplay between polyphosphate metabolism and nutrient availability is scrutinized, with implications for microbial ecology, agricultural practices, and biotechnological applications. By integrating current research findings, this review emphasizes the significance of polyphosphates not only as energy reservoirs but also as key players in nutrient cycling and environmental sustainability, underscoring their importance in both basic and applied biological sciences.