Determination of performance response of broilers to fermented tropical leaf meal supplementation using meta-analytical method.

Fermented tropical leaf meals (FTLM) are currently added to chicken feed to improve chicken productivity due to their reported nutritional and medicinal benefits. However, the effects of FTLM on broiler productivity and health are less clear. Thus, this meta-analysis was designed to assess the effects of FTLM on the performance outcomes of broilers Eleven controlled studies were retrieved and used to explore the impacts of dietary FTLM supplementation on growth performance [feed intake (FI), feed conversion ratio (FCR), average daily gain (ADG)], blood lipids, slaughter performance (abdominal fat, breast and thigh muscles weight), meat quality [pH, drip loss, shear force, lightness (L*), redness (a*), and yellowness (b*)], and intestinal histomorphology [villus height (VH), crypt depth (CD) and VH/CD values] of broilers. Subgroup and meta-regression analyses of the effects of moderators (i.e., leaf meal type, supplementation level, broiler strains, rearing phase, and fermentation microbes) on the growth performance of broilers were also assessed. Results show that dietary FTLM supplementation increased FI [standardised mean difference (SMD) = 0.11; 95% confidence interval (CI): 0.02, 0.20; P < 0.0001], improved ADG (SMD = 0.33; 95% CI: 0.23, 0.43; P < 0.0001) and FCR (SMD = - 0.21; 95% CI: - 0.30, - 0.11; P < 0.0001) in broilers. In addition, FTLM enhanced slaughter performance, meat quality, and intestinal histomorphology of broilers. Broilers fed 0-5 g/kg feed FTLM had better FI, FCR, and ADG than the controls taking significant heterogeneity into account. Meta-regression revealed that analysed moderators influenced growth performance results and accounted for some of the sources of heterogeneity. It can be concluded that up to 5 g/kg of FTLM can be added to broiler feed to improve growth performance, intestinal histomorphology, slaughter performance, and meat quality without adverse effects on dressing percentage and blood lipid profiles.

Meta-analysis of blood indices and production physiology of broiler chickens on dietary fermented cassava intervention.

The effects of dietary fermented cassava on the blood constituents and production parameters of broiler chickens have been reported with variable outcomes. Therefore, this investigation aimed to explore the impacts of dietary fermented cassava on growth traits, blood constituents, visceral organ, and carcass characteristics of broiler chickens. Four databases were searched for studies that assessed responses of broiler chickens dietary fermented cassava. Eleven articles were used for the investigation, and data generated were analysed using OpenMEE software. A random effects model was used, and effect sizes were presented as standardised mean difference (SMD) at a 95 % confidence interval (CI). Sources of heterogeneity were evaluated using the following modifiers: broiler strain used, cassava form, feeding duration, type of microbes used for the fermentation, and inclusion level of cassava. Results indicate that fermented cassava-based diets increased feed intake (SMD = 0.38; 95 % CI: 0.11, 0.65; P = 0.006), feed conversion ratio (SMD = 1.26; 95 % CI: 0.91, 1.61; P < 0.001), white blood cells (SMD = 1.26; 95 % CI: 0.54, 1.98; P < 0.001), total serum protein (SMD = 1.23; 95 % CI: 0.41, 2.05; P = 0.003), serum cholesterol (SMD = 0.43; 95 % CI: 0.01, 0.85; P = 0.050), serum creatinine (SMD = 2.53; 95 % CI: 0.53, 4.53; P = 0.013), and serum uric acid (SMD = 4.33; 95 % CI: 6.25, 2.41; P < 0.001), but lowered average daily gain and carcass yield, taking heterogeneity into account. Results reveal that studied modifiers were responsible for the inconsistent results among authors. In conclusion, dietary fermented cassava negatively influenced carcass yield, growth performance, and aspects of blood indices of broiler chickens, but did not affect abdominal fat content, visceral organ weights, and cut-part weights. However, more innovative research is needed to improve the feeding quality of cassava using other biotechnological tools in order to maximise its potential as an energy source in broiler chickens.

A Meta-analysis of Responses of Broiler Chickens to Dietary Zinc Supplementation: Feed Intake, Feed Conversion Ratio and Average Daily Gain.

The importance of zinc (Zn) in broiler chicken nutrition is gaining attention due to the realization of its role in several enzymes and metabolic functions. This meta-analysis, therefore, aimed to synthesize pooled evidence on the effectiveness of Zn supplementation on enhancing feed intake, feed conversion ratio (FCR) and average daily gain (ADG) in broiler chickens. Thirty-seven peer-reviewed studies out of 436 identified from the search carried out in Scopus, Google Scholar and PubMed databases met the criteria for inclusion in this meta-analysis. Data were pooled and then disaggregated for moderators: broiler strains, sources of Zn, duration of Zn supplementation and Zn supplementation levels. All the analyses were conducted in Open Meta-analyst for Ecology and Evolution (OpenMEE) software. Pooled results indicate that Zn supplementation increased feed intake [standardised mean differences (SMD) = 0.34 g/bird/day; 95% confidence interval (CI) 0.27, 0.42)] and ADG (SMD = 0.43 g/bird/day; 95% CI 0.35, 0.50) in broiler chickens in comparison with the controls. Dietary Zn supplementation improves FCR (SMD = - 0.16 g/g; 95% CI 0.20, - 0.11), taking heterogeneity and publication biases into account. Restricted subanalysis showed that studied moderators influenced the outcomes of the meta-analysis. Meta-regression revealed that moderators explain about 38% of the sources of variations in the present study. This meta-analysis suggests that dietary zinc supplementation had a positive effect on growth performance indices in broiler chickens.

Enhancement values of cassava by-product diets on production and haemato-biochemical indices of sheep and goats: a review.

The competition for maize and soybean between humans and livestock for food has led to an increase in the cost of livestock feeds. Therefore, this has necessitated the search for alternative non-competitive feedstuffs in order to partially replace maize and soybean in small ruminant diets. The use of cassava products as a partial replacement for maize and soybean in small ruminant diet has been investigated. Cassava is a tropical crop, and its fodder is rich in crude protein (CP), minerals and vitamins with about 85% of the CP fraction exist as true protein. Cassava by-products are also high in nutrients and could contribute significantly to the nutritional needs of sheep and goats. Specifically, cassava leaves are high in CP (25.10%) with an amino acid composition similar to soybean. Evidence also exist that ruminal degradability of cassava fodder is similar to that of maize and soybean with comparable outflow rates (75%). However, the use of cassava fodder in livestock production is limited by the presence of cyanogenic glucosides (linamarin and lotaustralin) that releases hydrogen cyanide (HCN) known to cause pathophysiological changes in the liver of sheep and goats. Importantly, several processing techniques are well known to reduce or eliminate the concentrates of cyanogenic glucosides in cassava with great success. Blood chemistry and production indices of sheep and goats fed differently processed cassava by-product-based diets have been evaluated by different authors. This review revealed that cassava root sievate meal, cassava root meal and cassava peel meal are low in CP (2.29, 3.40 and 7.05%, respectively), while cassava leaf meal is high in CP (32.43%). Feed conversion efficiency of sheep and good fed cassava leaves were 9.49 and 11.24, respectively, indicating that goats utilize cassava leaves better than sheep. It is concluded that cassava by-products are low in quality protein and should be supplemented with other rich protein sources before their use in ruminant diets.

Supplementation of vitamin A to local chicken diets in tropical environment enhances seminal quality and blood testosterone concentration.

There is insufficient information on the role of micronutrient supplementation on the productivity of local breeder cocks in a tropical environment. The target of this research, thus, was to deduce the impact of dietary vitamin A incorporation on semen traits and testosterone concentration of local breeder cocks in a tropical environment. One hundred twenty-eight-matured Nigerian local breeder cocks aged 10-12 months were alloted to 4 groups (n = 32): a control group (A) was fed experimental diet supplemented with vitamin A at 0 IU/kg feed and supplemented groups (B-D) fed commercial poultry diet supplemented with vitamin A at 250, 500 and 750 IU/kg feed for 16 weeks. Every group was replicated 4 times with 16 birds in every a replicate. A quadratic typed optimization function was employed to determine the optimum vitamin A supplementation that statistically improved serum testosterone and semen quality indices in local breeder cocks. Semen profiling and serum testosterone concentration were analysed at week 4 (pre-supplementation period), and thereafter at weeks 4, 8 and 12 (supplementation period). Serum testosterone and semen quality indices at pre-supplementation period were similar (p < 0.05) among the groups. Birds on 500 IU vitamin A/kg diet produced sperm with highest (p < 0.05) active motile cells and normal morphology compared to birds on the other 3 diets. Local breeder cocks fed diets having 500 and 750 IU vitamin A/kg diet produced sperm with lowest (p < 0.05) sluggish motile cells compared with those fed the control diet. Semen pH, volume, sperm concentration (SC), acrosome morphology defects and serum testosterone concentration were not affected by vitamin A supplementation. The result of the quadratic optimization model revealed that sluggish motile sperm (Y = 41.098-10.230x + 0.903x2; r2 = 0.943, p = 0.039) and normal sperm morphology (Y = 82.665 + 8.834x - 1.500x2; r2 = 0.965, p = 0.001) was optimized (p < 0.05) at 5664 and 2945 IU/kg feed, respectively. However, other parameters estimated were not significantly influenced. It is concluded that vitamin A supplementation enhanced sperm quality in local breeder cocks.

Meta-analysis of the influence of phytobiotic (pepper) supplementation in broiler chicken performance.

The aim of the study is to use meta-analytical procedure to resolve uncertainty, identify knowledge gaps, and create new insights using published data on the phytobiotic effect of dietary pepper intervention on daily feed intake (DFI), average daily gain (ADG), and feed conversion ratio (FCR) in broiler chickens. The authors accessed AGORA, Scopus, ScienceDirect, and Google Scholar databases for primary studies published between 2011 and 2018 using combinations of different search terms. Fifteen studies were included to assess phytobiotic effect of pepper on DFI, FCR, and ADG in broiler chickens. Random-effects model (REM) was used to generate pooled effect estimates at 95% confidence intervals (CI). Analysis was performed using Open Meta-analyst for Ecology and Evolution (OpenMEE) software, while publication bias and source of heterogeneity were assessed using standard methods. Dietary pepper supplementation enhanced ADG (standardized mean difference (SMD) = 0.576, 95% CI 0.444 to 0.707, p < 0.001) and FCR (SMD = 0.325, 95% CI - 0.453 to - 0.196, p < 0.001) considering the presence of heterogeneity and publication bias. DFI (SMD = 0.052, 95%CI - 0.069 to 0.173, p = 0.403) was not significantly influenced by dietary pepper supplementation. Restricted subgroup analysis revealed that both black and red pepper increased ADG (p < 0.001). Broilers on black pepper intervention had better FCR (p = 0.002) than broilers on red pepper treatment. Higher (p < 0.05) DFI was obtained on broilers fed pepper-based diet at the rate of > 6 g/kg feed for 35 days. There was no association between DFI and explanatory variables (broiler strain used and number of broilers used), whereas study country influenced DFI (p < 0.001). Furthermore, there was an association between outcome of interests (ADG and FCR) and explanatory variables (supplementation level, study country, number of broilers used per treatment group, and broiler strain used). Broilers on dietary pepper intervention for 42 days had higher ADG (SMD = 62.2 g/bird/day, p < 0.001) than those on dietary pepper intervention for 56 days (SMD = 35.7 g/bird/day, p = 0.002). There is evidence of heterogeneity, and meta-regression analysis showed that study country, supplementation level, and broiler strain used explained most of the sources of heterogeneity. The results of the present study revealed the potential of dietary pepper intervention to improve production efficiency in broiler chickens. The current meta-analysis also set the steps for standardized experimental designs on the use of dietary pepper intervention in broiler feeding trials in the future.