Effects of Cassava (Manihot Esculenta Crantz) Root Meal in Diets Containing Corn Dried Distillers Grains With Solubles on Production Performance, Egg Quality, and Excreta Noxious Gas Emission in Laying Hens

Utilisation of cassava as energy and protein feed resource in broiler chicken and laying hen diets

A detailed understanding of the nutrient contents of cassava products is crucial to fully maximise their utilisation in animal feed. This study aimed to review published data on the nutritional quality of cassava products and their use as a source of energy and protein in broiler chicken and laying hen diets. Cassava is a tuber crop that grows abundantly in tropical countries, and its products are classified as energy or protein feed resources based on their protein and energy levels. Cassava starch residue (CSR), cassava root meal (CRM), cassava peel meal (CPM), ensiled cassava peel meal (ECPM), fermented cassava peel meal (FCPM), cassava pulp, and cassava root sievate meal (CRSM) were classified as an energy source in chicken feed, whereas cassava leaf meal (CLM) is classified as a protein source. Nutritional analysis indicates that cassava leaves are high in protein, fibre, minerals, vitamins (B₁, B₂, and C), and carotenoids, while CRM is rich in energy but low in crude protein (CP). Additionally, cassava contains cyanogenic glycosides, especially linamarin, and lotaustralin, which release toxic hydrogen cyanide (HCN) upon tissue disruption. The utilisation of cassava as an energy or protein feed resource in the chicken diet is limited by its high fibre, presence of HCN, nutrient imbalance, and dusty nature of its dried meals. Efforts have been made to enhance the nutrient quality of cassava and increase their utilisation in chicken feed using different processing techniques with some success. Available information on the nutrient contents of differently processed cassava and its effect on chicken performance is vast and dispersed, making it hard to use such information in the decision-making process. Therefore, this review aimed to aggregate published articles on the nutrient contents of cassava products and their impacts on the health and productive indices of broiler chickens and laying hens into a single document for ease of comparison and decision-making.

Meta-analysis of the influence of dietary cassava on productive indices and egg quality of laying hens

There are an increasing number of studies on the effect of cassava (Manihot esculenta Crantz) on performance of laying hens with inconsistent outcomes. This study, therefore, used a meta-analytic approach to examine the effect of cassava-based diets on feed intake (FI), feed conversion ratio (FCR) end production data such as hen day egg production (HDEP), egg weight (EW), egg mass (EM), Haugh unit (HU), shell weight (SW) and shell thickness (ST) in laying hens. Two hundred and three studies were identified in a search performed in PubMed, Scopus and Google Scholar databases of which thirteen studies were suitable for the meta-analysis. Subgroup and meta-regression analyses were performed to explore the responses of laying hens to dietary cassava and sources of heterogeneity, respectively using the following moderators: study continent, cassava type, cassava processing methods, inclusion level, layer strain, feeding durations, number of layers and hen's age. Data were pooled using a random-effects model and statistical analyses were performed in OpenMEE software. Results show that cassava increased FI (mean difference MD = 0.97 g/d; 95% confidence intervals (CI) 0.05, 1.90) and reduced egg weight (MD = -0.72 g; 95% CI -1.26, -0.19) and SW (MD = -0.11 g; 95% CI -0.18, -0.04) when compared to control. Laying hens fed cassava diets had HDEP, FCR, EM, ST and HU values that compared favourably with the controls. Subgroup analysis demonstrated that inclusion of cassava at ≤ 25% in layer diets had no deleterious effects on measured outcomes taking cognizance of significant heterogeneity. However, meta-regression results showed that most of the sources of heterogeneity were explained by the studied moderators. In conclusion, ≤25% of cassava (CRM and CPM) can be included in layer diets without adverse effects on feed intake, feed conversion ratio and egg production characteristics, indicating that cassava has a very bright future as an energy source in the diets of laying hens.

A review of limitations to using cassava meal in poultry diets and the potential role of exogenous microbial enzymes

Cassava (Manihot esculenta), a crop grown in the tropics, is increasingly becoming a vital feed resource for human beings and livestock. Traditionally, cassava has been used primarily as a source of food for humans. However, it is becoming an increasingly important ingredient in livestock feed. The use of cassava leaves and roots in poultry diets is limited because of nutrient imbalances and toxins (hydrogen cyanide (HCN)) found in them. High HCN is reduced to innocuous levels by processing the ingredient using a simple sun drying method. Plant fibre content can be reduced and made available for use by poultry through the use of exogenous enzymes. More recent innovative interventions in biotechnology have brought about various exogenous enzymes that can help improve the digestibility of fibrous diets. These include, among others, carbohydrases, proteases and phytases. The extent to which the animals utilise nutrients is influenced by the type of enzyme and the physicochemical properties of the feed ingredient. This review aims to collate information on the current state of knowledge on the use of exogenous microbial enzymes in diets containing cassava and how the enzymes that target carbohydrates might be useful in making nutrient available for poultry.

Krill Meal Enhances Antioxidant Levels and n-3 Fatty Acid Content of Egg Yolk from Laying Hens Fed a Low-Pigment Diet

This study was conducted to determine effects of krill meal supplementation on production performance, egg quality, antioxidant substances, and fatty acid composition of egg yolk from hens fed a low-pigment diet. A total of 640 laying hens (Lohmann Brown), which were each 25 weeks old, were divided into 4 dietary treatment groups. Each treatment consisted of 8 replications with 20 laying hens per replication. The treatments were corn-soybean meal basal diet (CS), CS with 7.5% cassava meal (low-pigment; LP), and LP with 1.5 or 3% krill meal. All dietary treatments were formulated to be isocaloric (2,750 kcal/kg metabolizable energy) and isonitrogenous (17.5% crude protein). Birds were raised in an evaporative cooling system house for 8 weeks (25-33 weeks of age). Water was provided ad libitum and feed was provided according to breed requirement recommendations. The LP diets supplemented with krill meal had no effect on production performance and egg quality compared to those of the CS group (P>0.05). However, the LP diet caused a significant reduction in yolk color score, and astaxanthin, vitamin A, and vitamin E contents of egg yolk (P<0.05). However, the contents of these nutrients increased as the level of krill meal was increased in the diets (P<0.05). The highest yolk color score, and astaxanthin, vitamin A, and vitamin E contents were observed in laying hens fed 3% krill meal (P<0.05). The LP diet had no effect on n-3 fatty acid content; however, a significant reduction in the content of n-6 fatty acids, especially linoleic acid was observed (P<0.05). Further reduction occurred when higher level of krill was used in the diets (P<0.05). An increase in krill meal level significantly increased docosahexaenoic acid but not linolenic acid content of egg yolk. Krill meal, therefore, could be used to produce docosahexaenoic acid and antioxidant enriched eggs.