1.1 Introduction
Feeding intensity in aquaculture refers to the rate, frequency, and quantity of feed supplied to fish within a given period, which directly influences feed utilization efficiency, growth performance, and survival rate. In larval fish culture, feeding intensity is particularly critical because larvae are in a rapid phase of morphological and physiological development, requiring precise nutritional input to support organ formation, metabolic activity, and overall growth (Jobling, 2012). African catfish (Clarias gariepinus) is one of the most widely cultured freshwater fish species in Africa due to its fast growth rate, adaptability to diverse environmental conditions, and high market demand. However, its successful production is strongly dependent on effective larval rearing practices, especially feeding management during the early life stage.
This chapter will address the background information that motivated this study, the challenges that prompted it, its aim, and its objectives as a preface to subsequent sections of the study. Additional factors include the study's significance, scope, limitations, research questions, and the definition of technical terms.
1.2 Background of Study
African aquaculture has continued to experience rapid growth over the past decades due to increasing demand for affordable animal protein and the declining supply from capture fisheries. According to the Food and Agriculture Organization, aquaculture now contributes more than half of global fish consumption, with African catfish (Clarias gariepinus) being one of the most widely cultivated freshwater species in sub-Saharan Africa. Its popularity is attributed to its fast growth rate, tolerance to poor water conditions, high fecundity, and strong market acceptance. However, successful production of this species depends heavily on effective hatchery management practices, particularly during the larval stage where survival and growth are most vulnerable (FAO, 2022).
Jobling (2012) asserted that feeding intensity, which refers to the frequency and quantity of feed supplied to fish, plays a central role in determining feed utilization efficiency and growth performance in aquaculture systems. He further stated that inappropriate feeding strategies, such as overfeeding or underfeeding, may disrupt water quality and physiological balance in fish larvae. In African catfish hatcheries, larval rearing is particularly challenging due to the delicate nature of the early developmental stages. According to FAO (2022), hatchery operators in many developing regions still rely on traditional feeding practices that are not scientifically optimized, resulting in inconsistent growth rates and high mortality levels. This inconsistency is often linked to the use of different feed types such as live feeds (e.g., Artemia nauplii and zooplankton) and artificial microdiets, each of which varies significantly in nutrient composition, digestibility, and attractiveness to larvae.
Kestemont et al. (2007) stated that, live feeds are often preferred during the early larval stages because they stimulate natural feeding behavior and improve ingestion rates. They contended that live feeds enhance survival and growth due to their high nutritional quality and mobility, which attract larval fish more effectively than inert diets. However, they also reported that reliance on live feeds increases production cost and may introduce pathogens into the culture system. On the other hand, formulated diets offer advantages in terms of cost-effectiveness, ease of storage, and controlled nutrient composition, but their effectiveness depends largely on proper formulation and feeding management.
According to Ayinla (2003), African catfish larvae exhibit varying feeding intensities depending on environmental conditions, feed type, and stocking density. He affirmed that optimal feeding frequency improves nutrient absorption and growth performance, while irregular feeding schedules result in competition among larvae, reduced feed conversion efficiency, and stunted growth. Jobling (2012) affirmed that, overfeeding in larval fish culture leads to increased ammonia concentration and reduced dissolved oxygen levels, which negatively affect fish health and survival. He contended that maintaining appropriate feeding intensity is essential not only for growth optimization but also for maintaining stable water quality conditions in intensive aquaculture systems. In contrast, underfeeding results in poor weight gain, delayed development, and increased susceptibility to diseases due to weakened immune response.
This study is set against the backdrop of improving larval fish production efficiency through the evaluation of feeding intensity of African catfish (Clarias gariepinus) larvae fed different diets and its effects on growth and development.
1.3 Statement of Problems
Investigation revealed that aquaculture production continues to expand globally, yet the success of fish farming largely depends on early larval nutrition and feeding management, especially in species such as African catfish (Clarias gariepinus). In many hatchery systems, larval feeding intensity and diet composition is a critical determinant of survival rate, growth performance, and proper organ development. Inadequate or inconsistent feeding practices during the larval stage is associated with poor weight gain, stunted growth, and increased mortality, which significantly affects overall production efficiency (FAO, 2022).
Additionally, even when quality feeds are available, improper feeding intensity such as overfeeding or underfeeding may lead to deteriorating water quality, stress conditions, and reduced feed conversion efficiency, which ultimately affects larval survival and development. Overfeeding increases ammonia accumulation in culture water, while underfeeding leads to competition, cannibalism, and weakened immune response among larvae (Jobling, 2012).
Furthermore, environmental and management factors such as water temperature, stocking density, and feeding frequency interact with diet quality to influence larval performance. However, most existing studies have focused more on juvenile or adult stages, leaving a gap in knowledge regarding optimal feeding intensity during the early larval phase, which is considered the most sensitive stage in the life cycle of Clarias gariepinus. It is against this backdrop that this study seeks to investigate the feeding intensity of African catfish (Clarias gariepinus) larvae fed different diets and its effects on growth and development.
1.4 Aim and Objectives of Study
The aim of this study is to assess how feeding intensity and different diets influence the growth and development of African catfish larvae. In achieving this aim, the following specific objectives were laid out as follows:
- To determine the effect of different feeding intensities on the growth performance of Clarias gariepinus larvae.
- To evaluate the influence of different diets on larval survival rate.
- To assess the interaction between feeding intensity and diet type on larval development.
- To compare weight gain and length increment of larvae under different feeding regimes.
- To determine the optimal feeding intensity for improved larval performance.
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