Cassava-based Diets Research Articles

Improving the yield and nutritional quality of cassava (Manihot esculenta Crantz) in the rainforest agro-ecological zone of southeast Nigeria through agronomic biofortification with micronutrients

Cassava (Manihot esculenta Crantz) is an important staple crop, especially for resource-poor populations. Cassava-based diets are rich in calories but grossly deficient in essential mineral elements. A field study in southeastern Nigeria aimed at increasing yields and concentrations of bioavailable mineral elements in a β-carotene cassava variety, UMUCASS 38 (TMS 01/1371), through agronomic biofortification. A randomized complete block design experiment in triplicate, with foliar application of Zn (3.0 kg ha−1 Zn as ZnSO4), I (4.0 kg ha−1 I as KI), Se (0.25 kg ha−1 Se as Na2SeO3) and Zn + Se + I in combination at vegetative, tuber initiation and bulking stages of cassava. Results indicated neither phytotoxicity nor altered physical and chemical soil properties. Application of Zn or Zn + Se + I at the vegetative stage significantly increased cassava tuber yields. More Zn, Se, and I accumulated in fresh and processed cassava tuber products (gari, lafun), especially when Zn + Se + I was applied at tuber initiation stage. The combined application of Zn + Se + I consistently outperformed sole applications indicating a synergistic interaction effect between the three elements. It is concluded that in the Zn-deficient soils of southeast Nigeria, yield of cassava root tubers can be significantly increased by foliar application of Zn-containing fertilizer at the vegetative stage, but for optimal accumulation of elemental Zn, Se, and I, a combined Zn + Se + I fertilizer be applied at the tuber initiation stage.

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.

Evaluation of calcium and vitamin D3 in cassava-based diets on internal and external qualities of chicken eggs

The aim of this study was to evaluate the effect of calcium and vitamin D3 in cassava-based layers' diet on the external and internal qualities of egg. One hundred and thirty-five, ISA brown layers aged 54 weeks were assigned randomly to 9 treatment (T) combinations with three replicates in a 3×3 factorial arrangement in a completely randomized design. Each replicate had five hens while the diets were: T1 = 3.5% Ca and 1000 IU vitamin D3 , T2 = 3.5% Ca and 2000 IU vitamin D3 , T3 = 3.5% Ca and 3000 IU vitamin D3 , T4 = 4.5% Ca and 1000 IU vitamin D3 , T5 = 4.5% Ca and 2000 IU vitamin D3 , T6 = 4.5% Ca and 3000 IU vitamin D3 , T7 = 5.5% Ca and 1000 IU vitamin D3 , T8 = 5.5% Ca and 2000 IU vitamin D3 , and T9 = 5.5% Ca and 3000 IU vitamin D3 . After 12 weeks, two eggs were collected per replicate to assess the 3 external and internal egg qualities. The increasing levels of calcium and vitamin D3 had no effect on the external and internal qualities of the eggs. From the result, hens that were fed 4.5% and 5.5% Ca recorded highest shell thickness. The interaction of calcium and vitamin D3 affected the shell thickness with hens fed diet T5 (4.5% Ca with 2000 IU) recording the thickest egg shell while T2 (3.5% Ca with 2000 IU) recorded the lowest. It was therefore concluded that 4.5% and 5.5% dietary calcium, 1000 IU and 3000 IU vitamin D3 were best when used individually in the diet for hens while T5 (4.5% calcium with 2000 IU) favoured eggs shell thickness for hens aged 54 -66 weeks. Une augmentation de la production des chevres dans les zones tropicales a conduit à une concurrence continue avec les humains pour la nourriture car la plupart des protéines étant donné les aliments conventionnels (gâteau à l'arachide, gâteau palmiste, soja) entre autres sont de plus en plus rares et coûteux, il est donc nécessaire de trouver du matériel d'alimentation non conventionnel qui peut remplacer considérablement les aliments conventionnels sans conséquences négatives sur l'animal. Ce travail de recherche visait donc les caractéristiques de performance des chèvres naines d'Afrique de l'Ouest (le 'WAD') nourries de grainesde testaà base de cacao (le 'CST') en remplacement du supplément de concentré de gâteau au palmiste à un régime basal d'herbe. Douze chèvres naines d'Afrique de l'Ouest de 15 à 16 mois avec un poids moyen de 16.5 kg ont été utilisées pour l'expérience. Ils ont été attribués au hasard à trois régimes concentrés de telle sorte que 0%, 50%, 100% étaient pour le groupe A, B et C, respectivement du gâteau de palmiste (le 'PKC') ont été remplacés par des testicules de graines de cacao (le 'CST'). Chacun des trois groupes a été élevé sur l'un des suppléments de concentré alimentés à un régime basal de l'herbe (Cynodonnlemfuensis). L'expérience a duré six semaines, au cours de laquelle deux semaines ont été utilisées pour acclimatiser les animaux aux cages. Le résultat de l'expérience a montré une différence significative (P<0.05) dans l'apport alimentaire global moyen, le poids gagné et le ratio de conversion des aliments pour animaux parmi les traitements. Le gain de poids quotidien moyen et le gain de poids global parmi les groupes de traitement étaient significativement différence (P<0.05). Les chèvres nourries de régime B utilisé l'alimentation mieux avec un gain de poids de 2539.96 g suivie par ceux de l'alimentation C avec gain de poids de 1969.94 g. L'inclusion de graines de testa à base de cacao de 50 % à 100 % de remplacement pour le gâteau au palmiste améliore la croissance de la chèvre naine d'Afrique de l'Ouest.

Utilization of raw, cooked or fermented cassava-urea meal in a total diet for growing ewe-lambs

The nutritive value of cassava meal (CM), raw cassava-urea meal (RCU), cooked cassava-urea meal (CCU), and fermented cassava-urea meal (ECU) mixed with other ingredients were evaluated in this study using West African dwarf sheep. Twenty ewe-lambs (6 months old) and twelve ewes (12 months old) were respectively used for growth and metabolic investigations. Dry matter (DM) intake was 2,1 3, 3.25, 3.20 and 3.35 % BW; growth rate 48.3, 67.5, 86.9 and 88.3 g/day; and feed conversion ratio (FC7R) was 8.76, 7.54, 6.49 and 6.52 for CM, RCU, CCU and ECU respectively. DM digestibility was 58.5, 68.4, 73.3 and 72.5 % while nitrogen retention Was 40.5, 30,9, 46.3 and 45.4 % for CM, RCU, CCU and FCU respectively. Nutrient utilization and growth of ewe-lambs fed cassava-based diets improved with addition of urea to cassava meal. Cooking or fermentation further improved nutritive value and feed conversion ratio of cassava-urea meal. Since fermentation requires less labour and energy costs than cooking, it may be the preferred option for processing cassava-urea mixtures for ruminant feeds by resource-poor farmers in Nigeria.

Broken rice in a fermented total mixed ration improves carcass and marbling quality in fattened beef cattle.

ObjectiveThis study aimed to determine the effects of replacing cassava chips with broken rice in a fermented total mixed ration diet on silage quality, feed intake, ruminal fermentation, growth performance, and carcass characteristics in the final phase of fattening beef cattle.MethodsEighteen Charolais-Thai native crossbred steers (average initial body weight: 609.4±46 kg; average age 31.6 mo) were subjected to three ad libitum dietary regimes and were maintained in individual pens for 90 d before slaughter. The experimental design was a randomized complete block design by initial age and body weight with six replicates. The dietary regimens used different proportions of broken rice (0%, 16%, and 32% [w/w] of dry matter [DM]) instead of cassava chips in a fermented total mixed ration. All dietary treatments were evaluated for in vitro gas production and tested in in vivo feeding trials.ResultsThe in vitro experiments indicated that organic matter from broken rice was significantly more digestible than that from a cassava-based diet (p<0.05). Silage quality, nutrient intake, ruminal fermentation characteristics, carcass fat thickness, and marbling score substantially differed among treatments. The ruminal total volatile fatty acids, propionate concentration, dietary protein intake, and digestibility increased linearly (p<0.05) with broken rice, whereas acetate concentration and the acetate:propionate ratio decreased linearly (p<0.05) with broken rice (added up to 32 g/kg DM). Broken rice did not influence plasma metabolite levels or growth performance (p>0.05). However, the marbling score increased, and the carcass characteristics improved with broken rice.ConclusionSubstitution of cassava chips with broken rice in beef cattle diets may improve fattened beef carcass quality because broken rice increases rumen fermentation, fatty acid biosynthesis, and metabolic energy supply.

The Weight Gain and Growth of Crossbred Bulls Fed Locally Inspired Supplements Compared with Current Feeding Systems in Village Smallholdings in Malang, East Java

Growth rates of cattle in village smallholder farms are often low (0,2-0,5 kg/d) due to the ration formulation not meeting the nutrient requirements for cattle to achieve their potential live weight gain. This experiment aims to determine the growth of crossbred bulls fed a range of supplemented diets using local products comparing them to current traditional feeding system. This village was conducted in Kucur village, Dau sub-district, Malang. Fifyt cross bred aged between 1.5-2 years were allocated into five treatments; cassava-based diet by recent ACIAR-UB experiment (T1), commercial concentrate (T2), YaYa diet (T3), Santos diet (T4) and current feeding system (CFS) by smallholder farmers (T0) as the control. Cassava-based diet (T1) consisted of 50% cassava, 25% copra meal (CM) and 25% palm kernel cake (PKC). Local concentrate (T2) was bought from local cooperative in Malang. Yaya diet (T2) consisted of 30% cassava, 20% corn cob, 20% copra meal, 20% palm kernel cake and 10% rice bran. Santos diet (T4) consisted of 40 % corn cob, 20% palm kernel cake 20% rice bran, and 20% wheat pollard. Control treatment (T0) was 1 kg wheat pollard a day which was the general current feeding system by local smallholders. The experiment found that cassava-based diet (T1) supplementation showed the highest body growth compared to the other diets.

Konzo outbreak in Zambia linked to cassava-based diet.

Konzo outbreak in Zambia linked to cassava-based diet.

Influence of different levels of calcium and vitamin D3 in cassava-based diet on the performance of laying hens

This study was conducted to determine the influence of different levels of calcium and vitamin D3 in a cassava-based diet on performance of laying hens. One hundred and eight Isa Brown hens which were 34 weeks' old were used in a three by two factorial arrangement in a complete randomized design. Birds were fed diets containing different levels of calcium (A= 2.5%, B= 3.5%, and C= 4.5%), with each calcium level also containing vitamin D3 at levels of 2000, 4000 and 6000 IU. All birds were raised under the same management condition within the nine treatment combinations which had three replicates of four (4) birds each. Records of the feed intake, egg lay, cost of feed ingredients and mortality were documented. The records were used to calculate the hen-day production (HDP), feed intake, number of eggs laid per hen, dozens of eggs laid per hen, feed consumed per dozen egg, feed cost per dozen egg produced and mortality. The result obtained showed that diets B (3.5%), C (4.5%), the 2000 IU vitamin D3 level and diet C (4.5% calcium) containing 2000 IU vitamin D3 were better in terms of the number of eggs laid per egg, hen day production, and dozen egg per hen. Thus, farmers can use 3.5%, 4.5% calcium levels or 2000 IU vitamin D3 levels singly/individually in diet for laying hens and obtain better result. However, the C diet (4.5% calcium) containing 2000 IU vitamin D3 which had the highest number of eggs, HDP, dozen egg per hen, best feed conversion to eggs as well as the least cost of production is recommended for laying hens in the humid tropics, when calcium and vitamin D3 are used together in a cassava-based diet to feed hens

EVALUATION OF NUTRITIONAL EFFECTS AND DIGESTIVE BALANCE OF THREE CASSAVA-DISHES COMMONLY CONSUMED IN CÔTE D'IVOIRE AT WISTAR RATS

Valuing local dishes can help eradicate undernourishment in west Africa. In this context, the aim of this study is to evaluate in wistar rat nutritional effects and digestive balance of attiéké, attoukpou and placali, three cassava-dishes, commonly consumed in Côte d'Ivoire. For this purpose, 5 diets were composed to conduct growth and digestive balance experiments in wistar rats. Staple foods of the five diets are cassava-based foods (attiéké, attoukpou and placali), potatoes starch and sucrose. Four diets contain 45% of starch from different foods (attiéké, attoukpou, placali and potato). The last diet is starch-free, and contains sucrose as source of carbohydrate. This study showed that, cassava based-diets (attiéké, attoukpou and placali) have resulted in very good growth of rats, the efficiency of these foods is better, starch of cassava dishes has a digestibility greater than 95%. However, because of the difference in culinary treatments, nutritional performance of attiéké is reduced compared to attoukpou and placali. Cassava-based foods, mainly attoukpou and placali, favored protein utilization in rat growth. Diets based on potato starch and sucrose have the lowest feed efficiency and a very low growth performance in rats. Consumption of Cassava dishes may therefore dampen undernourishment.

Performance and Carcass Quality of Broier Placed on Pro-Vitamin A Cassava and Sweet Cassava-Based Diets

This experiment was carried out to determine the performance and carcass quality of broilers placed on pro-vitamin A cassava and sweet cassava-based diets using maize-based diet as control. The results show that daily weight gain of birds placed on maize-based diet (19.67g) was statistically higher (p 0.05) among themselves. The average daily feed intake of the maize- based diets (54.07g/day) was significantly higher (p 0.05) between each other. The feed conversion ratio of 2.75 for maize, 3.52 for sweet cassava and 3.26 for pro-vitamin A cassava did not show any significant difference (p>0.05) among the diets. The carcass weight showed a higher result in maize-based diet (743.18g), followed by pro-vitamin A cassava diet (681.32g) and sweet cassava showing the least result (655.28g). However there is no significant difference (p>0.05) among the diets. The cost of production was highest with maize based diets ( N 1,305.79) while that of sweet cassava (N736.94) and pro-vitamin A cassava (N982.91) were cheaper showing 43.56% and 24.73% cost reduction respectively. The lower cost of production with sweet cassava and pro-vitamin A cassava compensates the lower growth rate, suggesting that any of these variety of cassava can totally replace maize in broiler diet without any deleterious effect when properly processed to reduce the cyanogenic content of the cassava to non-toxic level.

Performance of Broiler Finisher Placed on Different Levels of Pro-Vitamin a Cassava-Based Diet

Performance of Broiler Finisher Placed on Different Levels of Pro-Vitamin a Cassava-Based Diet

Comparative effects of corn-based diet and phase-fed cassava-based diet on growth rate, carcass characteristics and lipid profile of meat-type ducks.

ObjectiveThis experiment was conducted to evaluate the effects of a corn- or cassava- based diet on the production of meat-type ducks.MethodsFour hundred day-old ducks were used in this experiment. They were divided into five groups with each group replicated eight times. The ducks fed the corn-based diets served as the control group. The four other groups comprised different treatments, with each one given the cassava-based diet based on phase-feeding. Three treatments were fed the cassava-based diet from 16, 28, and 35 d; respectively up to 42 d of age and the other group was fed the cassava-based diet from 1 to 42 d of age.ResultsThe results indicated that ducks on either the corn- or cassava-based diets were similar in growth during 1 to 9 d of age. However, toward 35 to 42 d, the cassava-diet produced a higher weight gain (p<0.05). The cassava-based diet was better than the corn-based diet at increasing the outer and inner breast weights at 28, 35, or 42 d (p<0.05). In contrast, the corn-based diet was better at increasing abdominal fat (p<0.05). The two diets did not differ in their effects on the serum triglyceride, cholesterol, high-density lipoprotein-cholesterol, low-density lipoprotein-cholesterol, very-low-density lipoprotein-cholesterol, and liver cholesterol. The corn-based diet, however, caused a highly significantly greater level of liver triglyceride (p<0.01).ConclusionThe results of this study suggest that both the cassava- and corn- based diets are similar in their effect on meat-type ducks during the starter stage but toward the finisher stage, the cassava-based diet has a better influence on weight gain and carcass characteristics.

Substitution of Wheat Bran by Cassava Flour in the Diet: Effect on the Growth of Chickens

Chicken diet cost represents up to 70 % of the production charges. Inputs, which are mostly imported products such as lysine, methionine, wheat bran are the cause of the expensive cost of foods. Wheat bran is not available in Côte d’Ivoire and could be efficiently substituted by cassava. Cassava is affordable and available all year round. The objective of this work was to determine the effects of the substitution of wheat bran by cassava flour on the growth of chickens. After administering ad libitum during 8 weeks the different food categories (starting and growing food), results showed that protein, fat, ash and calcium contents improved more with the addition of cassava for both starting and growing periods. The energy value of cassava-based feed was higher than that of foods containing wheat bran: 12 155 kJ / kg against 11 428 kJ / kg for the starting food and 12 586 kJ / kg against 11 577 kJ / kg for growth, respectively. Throughout the rearing period, the growth of chicken fed with the cassava-based diet was much higher than that of the chicken fed with the control diet. In the growing food, palmitic acid was the dominant saturated fatty acids with the cassava-based diet exhibiting higher values of saturated fatty acids. The content of unsaturated fatty acids from cassava (48.6 %) was slightly higher than the control diet (47.6 %). Except magnesium, macro-element concentrations were higher in the cassava-based diet than those of food control. Micronutrients such as manganese and zinc had a high value in cassava-based diet than the control diet. Hydrogen cyanide which is in the fresh pulp at 100 mg / kg, decreased at 1.8 mg / kg of dry matter in the start food and at 1.9 mg / kg of dry matter in the growth food. The substitution of wheat by cassava improves feed nutritional profile, also reduces the production cost, food industry will benefit from this up to 13, 36 % in start-up period and up to 13, 25 % in growing period.

Performance and Energy Requirements of Gestating Grasscutters Fed Agro-Industrial By-Products

The grasscutter (Thryonomys swinderianus) is a large herbivorous rodent of the grasslands of Sub-Sahara Africa. It is an important source of much-needed animal protein; and holds promise as an acceptable ‘bushmeat’ substitute for the hunted and endangered wildlife animal species of West Africa. The intensive production of the grasscutter would require the supply of inexpensive and adequate dietary nutrients. Energy requirement was determined using sixteen 8-months old gestating grasscutters. The grasscutters were separated into four groups and fed diets, which differed in their energy contents of 2000, 2200, 2400, and 2600 kilocalories metabolizable energy per kilogram (Kcal ME/kg). The test diets had the same crude protein (CP) level of 18%. The results showed that total feed intake was significantly (P<0.05) higher on the 2200 kcal ME/kg diet than on other diets. Weight gain was highest on the 2200 kcalME/kg diet. Average litter size was significantly (P<0.05) higher on the 2200 kcalME/kg and 2400 kcal ME/kg diets. The average birth weight of grasscutter pups was significantly (P<0.05) higher on the 2200 kcalME/kg and 2600 kcalME/kg diets. Taken together, growth and reproductive performance of gestating grasscutters was superior, on the 2200 kcalME/kg diet, to performance on other diets. The results of this study suggest that agro-industrial by-products, soybean and wheat offal in cassava-based diets, can effectively be used at dietary energy level of 2200 kcalME/kg, to rear gestating grasscutters. It is, therefore, concluded that the optimum dietary energy requirement of gestating grasscutters is 2200 kcal ME/kg.

Performance of Gestating Grasscutters (Thryonomys swinderianus) Fed Cassava-based Diets with Graded Protein Levels

Forages and crop residues are inexpensive and easily available feedstuffs for feeding grasscutters in captivity. These feedstuffs are nutritionally poor, not balanced for optimum performance and, therefore, required supplementation. Protein requirement of growing grasscutters was determined using thirty two 10-weeks old male grasscutters of equal weights. The grasscutters were separated into four groups and fed forage supplemented with concentrate diets, which differed in their protein contents of 8, 12, 16 and 20%, respectively but having the same energy level. Cassava root meal served as the main source of energy. The experiment, in a completely randomized design, lasted 10 weeks, during which feed intake and growth performance of the grasscutters were examined. Results showed that growing grasscutters were not significantly influenced by differences in the levels of crude protein in their diets. However, it appeared that grasscutters on the 12% crude protein diet ranked best in respect of feed intake and weight gain, while those on the 20% crude protein diet had the lowest feed intake and weight gain, but the best feed conversion ratio. The cost to gain ratio was significantly (P<0.05) influenced by the diets. Also, the cost effectiveness of diets increased with increase in dietary crude protein. It is, therefore, concluded that though the effect of crude protein levels on feed intake and weight gain were not significantly different, the higher ranking in respect of these parameters on the 12% crude protein diet suggests that the optimum crude protein requirement for growing grasscutters on cassava-based diets is 12%.

Overexpression of Hydroxynitrile Lyase in Cassava Roots Elevates Protein and Free Amino Acids while Reducing Residual Cyanogen Levels

Cassava is the major source of calories for more than 250 million Sub-Saharan Africans, however, it has the lowest protein-to-energy ratio of any major staple food crop in the world. A cassava-based diet provides less than 30% of the minimum daily requirement for protein. Moreover, both leaves and roots contain potentially toxic levels of cyanogenic glucosides. The major cyanogen in cassava is linamarin which is stored in the vacuole. Upon tissue disruption linamarin is deglycosylated by the apolplastic enzyme, linamarase, producing acetone cyanohydrin. Acetone cyanohydrin can spontaneously decompose at pHs >5.0 or temperatures >35°C, or is enzymatically broken down by hydroxynitrile lyase (HNL) to produce acetone and free cyanide which is then volatilized. Unlike leaves, cassava roots have little HNL activity. The lack of HNL activity in roots is associated with the accumulation of potentially toxic levels of acetone cyanohydrin in poorly processed roots. We hypothesized that the over-expression of HNL in cassava roots under the control of a root-specific, patatin promoter would not only accelerate cyanogenesis during food processing, resulting in a safer food product, but lead to increased root protein levels since HNL is sequestered in the cell wall. Transgenic lines expressing a patatin-driven HNL gene construct exhibited a 2–20 fold increase in relative HNL mRNA levels in roots when compared with wild type resulting in a threefold increase in total root protein in 7 month old plants. After food processing, HNL overexpressing lines had substantially reduced acetone cyanohydrin and cyanide levels in roots relative to wild-type roots. Furthermore, steady state linamarin levels in intact tissues were reduced by 80% in transgenic cassava roots. These results suggest that enhanced linamarin metabolism contributed to the elevated root protein levels.

The BioCassava Plus Program: Biofortification of Cassava for Sub-Saharan Africa

More than 250 million Africans rely on the starchy root crop cassava (Manihot esculenta) as their staple source of calories. A typical cassava-based diet, however, provides less than 30% of the minimum daily requirement for protein and only 10%-20% of that for iron, zinc, and vitamin A. The BioCassava Plus (BC+) program has employed modern biotechnologies intended to improve the health of Africans through the development and delivery of genetically engineered cassava with increased nutrient (zinc, iron, protein, and vitamin A) levels. Additional traits addressed by BioCassava Plus include increased shelf life, reductions in toxic cyanogenic glycosides to safe levels, and resistance to viral disease. The program also provides incentives for the adoption of biofortified cassava. Proof of concept was achieved for each of the target traits. Results from field trials in Puerto Rico, the first confined field trials in Nigeria to use genetically engineered organisms, and ex ante impact analyses support the efficacy of using transgenic strategies for the biofortification of cassava.

Assessing diet in populations at risk for konzo and neurolathyrism

Although both konzo and neurolathyrism are diseases associated with diet, we know surprising little about the diets of the groups at risk. The objective of this paper is to discuss methods for assessing dietary intake in populations at risk for konzo and lathyrism. These methods include weighed food records and interview based techniques like 24-h recalls and food frequency questionnaires (FFQs). Food records have the potential to provide accurate information on food quantities, and are generally the method of choice. Interview based methods provide less precise information on the quantities of foods ingested, and are subject to recall bias, but may be useful in some studies or for surveillance. Sample size needs to be adequate to account for day-to-day and seasonal variability in food intake, and differences between age and sex groups. Adequate data on the composition of foods, as actually consumed, are needed to evaluate the food intake information. This is especially important in the case of cassava and grass pea where the toxins in the diet is a function of processing. Biomarkers for assessing the cyanogen exposure from cassava-based diets are available; biomarkers for the β-ODAP exposure from grass pea diets need development.

Supplementation of Urea Level and Malate in Concentrate Containing High Cassava Chip on Rumen Ecology and Milk Production in Lactating Cows

Four, lactation dairy cows were randomly assigned according to a 2 x 2 Factorial arrangement in a 4 x 4 Latin square design to study supplementation of urea level (U) at 2 and 4 % and malate (M) at 10 and 20 g/hd/d in concentrate. The treatments were as follows U2M10, U2M20, U4M10 and U4M20, respectively. The cows were offered the treatment concentrate at a ratio to milk yield at 1:2.5 and urea-treated rice straw was fed ad libitum. The results have revealed that rumen fermentation and blood metabolites were similar for all treatments. The populations of protozoa and fungal zoospores were significantly different as affected by urea level and malate. In addition, the viable bacteria were similar for amylolytic and proteolytic bacteria. Cellulolytic bacteria were significantly affected by level of malate especially Selenomonas ruminantium and Megasphaera elsdenii while Butyrivibrio fibrisolvens was significantly affected by level of urea supplementation. Yield of milk was greatest in cows fed cassava-based diets with M20U2, but were lowest when receiving M10U4 in diets. In addition, production of 3.5%FCM exhibited similar results for all treatments. In conclusion, the combined use of concentrate containing high level of cassava chip at 75% DM with urea at 4% in concentrate and malate at 20 g/hd/d with UTS as a roughage could improved rumen ecology and microbial protein synthesis efficiency in lactating dairy cows.

Effect of Enzyme Supplemented Cassava Root Sieviate on Egg Quality Gut Morphology and Performance of Egg Type Chickens

Enzymic supplementation of cassava root sieviate (CRS) in cassava –based diet was investigated in layers. One hundred and twenty laying birds of Nera strain at 22 weeks old were divided into twelve groups and randomly assigned to the four groups of diets. It lasted for 84 days at the teaching and research farm of the university of Ibadan Nigeria. Results of control avizyme and dried pure yeast (DPY) supplemented diet were similar and significantly (P<0.05) higher than unsupplemented cassava diets. Feed intake revealed that layers fed cassava-based diet had lower consumption when compared to those fed control. Feed conversion however showed that those layers on DPY supplemented diet were significantly (P<0.05) better than others. Final body weight of the layers showed that those on control were significantly (P<0.05) heavier than others. The kidney, heart, abdominal fat and oviduct of layers cassava diet either supplemented or not were significantly (P<0.05) reduced when compared with others on control. The gizzard weight of layers fed unsupplemented and supplemented was also significantly (P<0.05) increased. No mortality was recorded during the feeding trial. Considering egg production layers on control performed better than others, economically DPY diet ranked second to control.