Nutritional and Anti-Nutritional Evaluation of Alternative Feed Ingredients for Sustainable Poultry Farming in Central and Southern Ethiopia

Sustainable poultry farming is vital for global food security, particularly in developing countries like Ethiopia, where demand for animal protein is rising (FAO, 2021). However, smallholder farmers face challenges due to the high cost and seasonal scarcity of conventional feed ingredients like maize and soybean meal, which account for 60–70% of production costs (Makkar, 2018; Adeyemo et al., 2022). To ensure sustainability, affordable, locally available feed alternatives must be explored without compromising poultry health and productivity (Pereira et al., 2019).

A promising solution is integrating alternative feed sources from underutilized plants and agro-industrial byproducts. This approach reduces reliance on costly commercial feeds while promoting circular agriculture and waste reduction. Moreover, using indigenous, climate-resilient resources enhances poultry farming’s adaptability to environmental changes, fostering long-term sector resilience (Makkar and Ankers, 2014).

Alternative feed ingredients, including cassava leaves (Manihot esculenta), sweet potato vines (Ipomoea batatas), and banana blossoms (Musa paradisiaca), have been identified as potential substitutes for conventional feeds, particularly in tropical regions (Olukosi et al., 2023). Sourced from agricultural byproducts or non-conventional crops, these ingredients are rich in protein, fiber, and essential minerals, making them valuable for poultry diets (Mlambo et al., 2013). However, their use is limited by anti-nutritional factors such as oxalates, tannins, and phytates, which reduce nutrient bioavailability and digestibility (Selle and Ravindran, 2007; Kumar et al., 2022).

When properly processed and balanced in formulations, these alternative feeds can sustainably enhance livestock nutrition—especially in regions where conventional feeds are costly or scarce. Further research supports their viability in animal diets (Olukosi et al., 2023). This study evaluates the nutritional composition and anti-nutritional factors of alternative feed ingredients used by smallholder poultry farmers in southern Ethiopia. The specific objectives are:

• To assess the nutritional composition of selected alternative feed ingredients for poultry.
• To identify and evaluate the major anti-nutritional factors present in these feed ingredients,
• To evaluate the associations between farmers’ preferences for alternative feed resources and laboratory analysis.

This study was conducted in the Wolaita, Gamo (Southern Ethiopia), and Hadiya (Central Ethiopia) Zones, where smallholder poultry production is widespread and farmers frequently rely on alternative feed resources such as crop residues, agro-industrial byproducts, and forage plants (Tadesse et al., 2020; Halima et al., 2012; Dessie and Ogle, 2001). Seasonal shortages and high costs of commercial feeds further drive the use of non-conventional ingredients (Bogale, 2008; Getu et al., 2014).

Data were collected through structured surveys and interviews with poultry farmers, alongside laboratory analysis of locally available feedstuffs. Sampled materials included Enset (Ensete ventricosum) corm, Cassava (Manihot esculenta) leaf, Sweet potato (Ipomoea batatas) leaf and root, Mango (Mangifera indica) seed kernel, Avocado (Persea americana) peel and seed kernel, Banana (Musa spp.) blossoms, and Chumadhe (Amaranthus retroflexus) powder meal (Kebede et al., 2021). These zones were selected due to their documented tradition of incorporating such resources into poultry diets (Mekonnen et al., 2019). Sampling prioritized ingredients that were both farmer-reported and nutritionally diverse to assess their potential as alternative feeds.

Table 1: Percentage of respondents using alternative feed ingredients.

Representative samples of locally available poultry feed ingredients were collected from smallholder farms across the study area. The collected samples included Enset corm (Ensete ventricosum), Cassava leaf (Manihot esculenta), Sweet potato leaf and root (Ipomoea batatas), Mango seed kernel (Mangifera indica), Avocado peel and seed kernel (Persea americana), Banana blossoms (Musa paradisiaca), and Amaranthus retroflexus powder meal. Following collection, all samples were air-dried and ground to pass through a 1-mm sieve to ensure uniformity prior to chemical analysis.

The proximate composition analysis followed standard AOAC (2019) methods, with moisture content determined by oven-drying at 105°C, crude protein measured using the Kjeldahl method, and crude fiber and ether extract quantified through fiber extraction and Soxhlet techniques respectively. Ash content was determined by incineration, while nitrogen-free extract (NFE) was calculated by difference. Metabolizable energy (ME) values were estimated using predictive equations based on the proximate composition results, following the methodology described by Scott et al. (1990).

ME (kcal/kg) =37×CP + 81×EE+ 35×NFE−44×CF

Where; CP, EE, CF, and NFE are expressed as percentages.

The mineral content of the feed ingredients was analyzed to determine levels of calcium, phosphorus, magnesium, iron, potassium, copper, and zinc. Atomic absorption spectrophotometry (AAS) was used for calcium, magnesium, iron, copper, and zinc measurements, while phosphorus was quantified using a colorimetric method (AOAC, 2019). Potassium levels were determined using a flame photometer. All analyses were performed in duplicate to ensure accuracy and reliability.

Anti-nutritional compounds such as oxalates, tannins, and phytates were assessed using standard laboratory procedures. Oxalate content was measured through titration with potassium permanganate (Day and Underwood, 1986). Tannin levels were determined via a colorimetric method using the Folin-Denis reagent (Makkar, 2003), while phytate content was analyzed using a spectrophotometric method based on the Wade reagent assay (Haug and Lantzsch, 1983).

Data were analyzed using SPSS version 26.0. A one-way ANOVA and Tukey’s post-hoc test (P < 0.05) determined significant differences among feed ingredients across three zones. Descriptive statistics summarized proximate composition, metabolizable energy, minerals, and anti-nutritional factors. Pearson correlation assessed associations between farmers’ preferences and lab results. Findings were presented in tables for comparison of nutritional and anti-nutritional components in poultry feed alternatives.

The study evaluated alternative chicken feed ingredients in the Wolaita, Gamo, and Hadiya zones of south and central Ethiopia (Table 1). Ensete ventricosum corm was the most widely adopted (69.4%), with significant regional variation (P = 0.0041), peaking in Wolaita (75.0%). Other prominent feeds included Persea americana seed kernel (63.8%, P < 0.001) and Mangifera indica seed kernel (51.7%, P = 0.002). Ipomoea batatas root (32.6%, P < 0.001) and leaves (28.5%, P = 0.045), Manihot esculenta leaves (39.7%, P < 0.001), and avocado peels (43.9%, P < 0.001) also showed zonal/regional differences. Less common options, such as Moringa pods (9.2%), banana blossom (14.6%), and Amarante reflechie powder (13.1%), exhibited no significant variation across zones.

The proximate composition (% DM) and metabolizable energy (ME, kcal/kg DM) of alternative chicken feed ingredients in Southern Ethiopia showed significant variations (P < 0.05) in nutritional components, including ash, moisture, crude protein, ether extract, crude fiber, nitrogen-free extract, and ME (Table 2). Cassava leaf meal had the highest ash content (13.3 ± 1.25%), followed by Moringa stenopetala pod (8.3 ± 1.52%) and sweet potato leaf meal (7.9 ± 0.4%), suggesting these feeds are rich in minerals. In contrast, Mangifera indica seed kernel (2.4 ± 0.14%) and banana blossom meal (1.6 ± 0.2%) had the lowest ash levels, indicating minimal mineral contributions. Crude protein content was highest in sweet potato leaf meal (27.0%) and cassava leaf meal (23.7%), while Ensete ventricosum corm contained the least (3.3%). Metabolizable energy varied considerably, with Persea americana seed kernel providing the highest ME (3542 kcal/kg DM) and avocado peel the lowest (1084 kcal/kg DM). Additionally, avocado peel had the highest crude fiber content (25.3%), which may limit its digestibility. These findings highlight the diverse nutritional profiles of alternative feed ingredients and their potential implications for poultry diets.

The mineral analysis revealed highly significant differences (P < 0.001) among feed ingredients (Table 3). Calcium was highest in Ensete ventricosum corm (316 ± 5 mg/100g DM) and Amarante reflechie powder meal (264 ± 9 mg/100g DM), while Mangifera indica seed kernel (0.51 ± 0.1 mg/100g DM) and avocado seed kernel (0.7 ± 0.1 mg/100g DM) had the lowest levels.

For phosphorus, Amarante reflechie powder meal (261 ± 5 mg/100g DM) and sweet potato leaf meal (217 ± 1 mg/100g DM) were the richest sources, contrasting with avocado seed kernel (18 mg/100g DM), which had the lowest content. Magnesium levels peaked in sweet potato leaf meal (212 ± 10 mg/100g DM), followed by Amarante

Table 2: Proximate composition (% DM) and metabolizable energy (Kcal/kg DM) of alternative feed ingredients for chickens.

a,bMean ± SD; values in the same column with different superscripts are significantly different (P < 0.05); SD: Standard deviation; NFE: nitrogen free extractives; ME: metabolizable energy.

Table 3: Minerals composition of alternative feed ingredients for chickens (mg/100g DM basis) in southern Ethiopia.

a,b,c,d,e,fMean ± SD, Values in the same column with different superscripts are significantly different (P < 0.05) as determined by the Duncan multiple range test; SD, Standard deviation. Ca: Calcium; P: Phosphorus; Mg: Magnesium; Fe: Iron; K: Potassium; Cu: Copper; Zn: Zinc.

reflechie powder meal (132 ± 13 mg/100g DM), while avocado peels contained the least (19 ± 2 mg/100g DM).

Iron was highest in Amarante reflechie powder meal (8 ± 0.8 mg/100g DM) and cassava leaf meal (7 ± 0.57 mg/100g DM), with avocado peels (0.5 mg/100g DM) showing minimal amounts. Potassium dominated in banana blossom meal (553 ± 8.8 mg/100g DM) and Amarante reflechie powder meal (525 ± 24 mg/100g DM), but was negligible in avocado peels (0.1 mg/100g DM).

Copper levels were exceptional in banana blossom meal (10 ± 1.5 mg/100g DM) and modest in Ensete ventricosum corm (3 ± 0.25 mg/100g DM), whereas mango seed kernel (0.15 mg/100g DM) and avocado seed kernel (0.2 mg/100g DM) were poor sources. For zinc, Ensete ventricosum corm (2.4 ± 0.1 mg/100g DM) and sweet potato leaf meal (2.2 ± 0.4 mg/100g DM) were superior, while banana blossom meal had the lowest content (0.2 ± 0.1 mg/100g DM).

These results highlight the variability in mineral profiles, with Ensete ventricosum corm, Amarante reflechie powder meal, and sweet potato leaf meal emerging as particularly valuable for addressing poultry dietary deficiencies.

The study revealed significant variations (P < 0.001) in anti-nutritional content among alternative chicken feed

Table 4: Anti-nutritional level of alternative and conventional feed ingredients for chickens (mg/100g DM basis) in southern Ethiopia.

a,b,c,d,e,fMean ± SD, Values in the same column with different superscripts are significantly different (P < 0.05); P: probability; inh: inhibitor.

ingredients in southern Ethiopia (Table 4). Key findings showed Persea americana peel contained the highest tannins (230 ± 10 mg/100g DM), while Ipomoea batatas root had the most phytates (50 ± 5 mg/100g DM) and Moringa stenopetala pod showed the highest oxalates (332.56 ± 1.6 mg/100g DM).

Oxalate levels were notably elevated in Moringa stenopetala pod, followed by cassava leaf meal (25 ± 1 mg/100g DM) and Amarante reflechie meal (24.33 ± 0.57 mg/100g DM). In contrast, banana blossom (0.26 ± 0.05 mg/100g DM) and sweet potato leaf meal (1.9 ± 0.36 mg/100g DM) contained minimal amounts.

Tannin concentrations were substantially higher in avocado peel compared to other ingredients, with cassava leaf meal (20.33 ± 1.52 mg/100g DM) and Moringa stenopetala pod (8.39 ± 0.53 mg/100g DM) showing moderate levels. Enset corm (0.17 ± 0.005 mg/100g DM) and banana blossom meal (0.35 ± 0.05 mg/100g DM) had negligible tannin content.

Phytate levels were prominent in sweet potato root and avocado peel (24 ± 2 mg/100g DM), while avocado seed kernel (0.2 ± 0.1 mg/100g DM) and banana blossom meal (0.43 ± 0.05 mg/100g DM) showed minimal amounts. Protease inhibitors peaked in avocado peel (50 ± 5 mg/100g DM), with sweet potato leaf meal (0.1 ± 0.00 mg/100g DM) and enset corm (0.2 ± 0.00 mg/100g DM) containing the lowest levels.

Goitrogens and lectins followed similar patterns, with avocado peel showing the highest concentrations (14.33 ± 2.08 mg/100g DM and 27 ± 2.5 mg/100g DM respectively). Cassava leaf meal contained moderate lectins (0.6 ± 0.1 mg/100g DM), while sweet potato leaf meal (0.1 ± 0.00 mg/100g DM) and enset corm (0.3 ± 0.00 mg/100g DM) had minimal levels.

These results highlight the importance of selecting feed ingredients with lower anti-nutritional content, such as banana blossom meal and enset corm, to optimize poultry nutrition and health. Proper processing methods should be considered for ingredients with higher anti-nutritional factors to enhance feed quality and chicken productivity.

Alternative Feed Ingredients Demonstrate Considerable Potential to Supplement Conventional Poultry Diets, Though their Adoption Requires Addressing Nutritional Limitations Through Proper Processing

Protein-rich options like sweet potato leaf meal (Wang et al., 2021) and cassava leaf (Adewumi et al., 2022) offer valuable nutrients but contain anti-nutritional factors including cyanogenic glycosides and high fiber content (25.3% in avocado peel; Agboola et al., 2023). Regional availability significantly influences utilization patterns, with Enset corm being prominent in Ethiopian poultry diets due to local cultivation (Tsegaye and Struik, 2021), while mango seed kernels gain preference in other tropical regions for their cost-effectiveness (Agboola et al., 2023). Effective processing methods like lactic acid bacteria fermentation can reduce tannins by 60% (Zhang et al., 2023), while combined soaking and thermal treatments improve mineral bioavailability by degrading oxalates and phytates (Kumar et al., 2022; Smith et al., 2023).

Ensete corm and Amarante powder meal provide substantial calcium and phosphorus (Adeyemi et al., 2022), crucial for skeletal development and egg production, though their benefits may be limited by mineral-binding anti-nutrients. Strategic interventions like phytase supplementation significantly improve phosphorus absorption (Johnson and Lee, 2023), while fermentation enhances calcium availability (Smith et al., 2023). For trace minerals, chelated forms of zinc and copper show particular promise in overcoming absorption barriers caused by phytates and fiber (Thompson et al., 2022; Wang et al., 2023). Potassium sources like Musa blossom meal support electrolyte balance, though optimal sodium-to-potassium ratios must be maintained to prevent absorption interference (Zhang et al., 2023).

Farmers can successfully incorporate processed alternatives like fermented avocado seed kernel at ≤20% inclusion (Dzomba et al., 2020), while researchers should prioritize optimizing enzymatic treatments (Adeola and Cowieson, 2023) and investigating long-term health impacts. Policy initiatives promoting affordable processing technologies (e.g., solar drying) could significantly enhance adoption in developing regions (Zhang et al., 2023). Critical research gaps remain in developing balanced formulations, scaling processing methods economically, and conducting thorough cost-benefit analyses - particularly in feed-insecure regions like southern Ethiopia where these alternatives could substantially improve poultry production sustainability (Melesse et al., 2023). Through coordinated efforts across these domains, alternative feeds can meaningfully contribute to more sustainable and resilient poultry production systems worldwide.

The results highlight the variability in anti-nutritional factors among alternative feed ingredients. Avocado peel consistently showed the highest levels of tannins, protease inhibitors, goitrogens, and lectins, making it a less suitable feed ingredient unless properly processed to reduce these compounds. Conversely, Banana blossom meal and Enset corm had relatively low levels of anti-nutritional factors, suggesting their potential as safer feed options.

The high levels of oxalates in Moringa stenopetala pod and phytates in Sweet potato root are concerning, as these compounds can significantly reduce mineral bioavailability. Oxalates can bind to calcium and other minerals, thereby reducing their absorption and potentially contributing to deficiencies (Smith and Johnson, 2023). Recent studies have emphasized the importance of dietary calcium-to-oxalate ratios in mitigating these effects (Khan and Iqbal, 2021). Similarly, phytates can chelate essential minerals such as zinc, iron, and calcium, impairing nutrient utilization (Smith and Johnson, 2023). Advances in phytase enzyme supplementation have been shown to effectively degrade phytates, improving mineral bioavailability in poultry diets (Zanu et al., 2020).

Tannins, found in high concentrations in avocado peel, have been shown to inhibit protein digestion and potentially reduce feed efficiency (Smith et al., 2023). Recent research has demonstrated that tannin-binding agents, such as polyethylene glycol, can neutralize tannins and improve nutrient utilization in poultry diets (Sharma et al., 2018). Protease inhibitors, which are also abundant in avocado peel, have been shown to interfere with protein digestion processes. This interference can lead to a reduction in the availability of essential amino acids, which are critical for supporting growth and production (Smith et al., 2023). Heat treatment and fermentation have been shown to significantly reduce protease inhibitor activity in plant-based feeds (Olukomaiya et al., 2020).

Goitrogens, which are present in significant amounts in avocado peel, have the potential to interfere with iodine metabolism. This interference can result in thyroid gland enlargement and a decrease in metabolic efficiency (Smith et al., 2023). Iodine supplementation has been recommended to counteract the effects of goitrogens in poultry diets (Surai et al., 2019). Lectins, which were also highest in Avocado peel, can bind to the intestinal lining, impairing nutrient absorption and causing digestive disturbances (Vasconcelos and Oliveira, 2004). Thermal processing and enzymatic treatments have been shown to reduce lectin activity effectively (Zhang et al., 2021).

Alternative feed ingredients—including avocado seed kernel (12.5 MJ/kg ME), Amaranthus meal (high phosphorus), Enset corm, mango seed kernel, and sweet potato products (root: 13.2 MJ/kg ME; leaf: 18–22% crude protein)—offer sustainable, cost-effective solutions to reduce reliance on conventional poultry feeds, particularly for smallholder farmers in regions like southern Ethiopia. While these alternatives provide comparable nutritional value (e.g., cassava leaf meal at 20–25% crude protein), their anti-nutritional factors—such as tannins in avocado peel (2.5–3.5%) and cyanogenic glycosides in cassava leaves (100–400 mg/kg)—require processing treatments like fermentation or heat to ensure safety and nutrient bioavailability. Further research is needed to optimize inclusion rates, refine processing methods, assess long-term impacts on poultry health, and evaluate economic feasibility for large-scale adoption. By addressing these challenges, these locally available resources could enhance poultry productivity, improve feed accessibility, and contribute to food security in feed-scarce regions.

For farmers and feed manufacturers, adopting processing methods—such as drying, fermentation, soaking, and enzymatic treatment can reduce anti-nutritional factors and improve feed quality, while balanced diets incorporating diverse alternative feed resources should be prioritized to ensure optimal nutrient intake. Supplementation is critical when using low-mineral ingredients (e.g., maize, Niger seed cake) to prevent deficiencies that impair growth and egg production, and farmers should seek guidance from extension services on proper preparation techniques. Researchers should focus on long-term studies evaluating nutrient bioavailability and poultry performance with alternative feeds, while policy makers can support adoption through farmer education programs and subsidies. Extension services play a key role in training farmers on the benefits, limitations, and proper processing of alternative feeds to maximize productivity, particularly in smallholder systems. Together, these strategies can enhance the sustainable use of alternative feeds in poultry production.

The authors extend their heartfelt gratitude to the Terfeza Development Association, with special thanks to Berket Tasew, as well as to Arba Minch University and the International Livestock Research Institute (ILRI) for their financial support of this research. Special appreciation is also extended to Kathy Marshall (Canada), owner of Saba Hari Campanie, for covering the cost of the article generator.

This study presents a novel and comprehensive evaluation of alternative poultry feed ingredients commonly used by smallholder farmers in the Wolaita, Gamo, and Hadiya zones of Ethiopia. Unlike previous studies that often focus solely on proximate composition, this research uniquely integrates farmers’ preferences with laboratory-based analyses of nutritional quality, mineral content, and anti-nutritional factors. It is the first of its kind to statistically correlate farmers’ feed selection decisions with scientific evidence, thereby bridging traditional knowledge and empirical validation. The study identifies locally available but underutilized resources such as Ensete ventricosum corm, Persea americana seed kernel and peel, and Amaranthus retroflexus meal, highlighting their diverse nutritional potentials and limitations due to high levels of anti-nutritional compounds. By mapping these ingredients’ energy, protein, and mineral values alongside anti-nutritional risks, the research provides an actionable framework for balanced feed formulation. Moreover, it lays the groundwork for future policy development and targeted extension services aimed at improving feed security, reducing production costs, and enhancing the sustainability of poultry farming in feed-scarce tropical regions.

Aklilu Getahun, Yisehak Kechero, Nebiyu Yemane, Tadelle Dessie and Wondeminhe Esatu have contributed equally to this full-length research article.

The author declares that there is no conflict of interests.