Effects of moringa oleifera leaf meal diets on growth performance, haematology and histopathology of key body organs in growing pigs

Abstract

This study was designed to determine the effects of inclusion, at varying levels of Moringa oleifera leaf meal (MOLM) in growing pig diets on voluntary daily feed intakes, growth performance, carcass quality, haematology, plasma lipid indices, gastrointestinal morphology, bacteriology and histopathology of the spleen, liver and kidneys. Twenty four (24) two and a half months (2.5) old pigs were selected and assigned to 4 treatment diets (T) containing 0% (T1), 3% (T2), 6% (T3) and 12% (T4) MOLM concentrations, each with 2 replications of 3 pigs. The voluntary daily feed intakes and weekly pig weights were recorded for 7 weeks after which 2 sets of blood samples were drawn from 2 pigs per replication for haematology and plasma lipid determination. These pigs were later sacrificed and one segment of tissue from the stomach, distal ileum, and proximal colon collected for histopathological analysis and their contents for pH measurements. Similarly, the spleen, liver and kidney samples were collected for histopathological studies. In addition, faecal samples from the rectum were collected for bacteriology. Data on the voluntary daily feed intakes, growth performance, blood characteristics, pH measurements and bacterial colony counts were analysed for descriptive statistics and ANOVA. Results revealed that the voluntary daily feed intakes for the 12% MOLM pigs were significantly higher than for the control, 3% and 6% MOLM groups. The 3% and 6% MOLM had significantly higher FCE compared to 12% MOLM and control groups. Inclusion of MOLM in the diet significantly increased haemoglobin concentration only to a level of 6% though there was a reduction in 12% MOLM. Also observed was higher Mean Cell Volume for the control compared to 6% MOLM pigs. Moringa oleifera leaf meal at 3% in the diet also increased the white blood cell counts compared to the control group. Total cholesterol in 3% MOLM group was significantly lower compared to those from control. Moringa oleifera leaf meal in the diet (>3%) led to the enlargement of splenic follicles (white pulp) as well as capsular and parenchyma fibroses. In the liver, increased MOLM in the diet led to loss of lobular architecture with damaged cellular outlines, dilation of sinusoidal spaces, vascular congestion and occasional nuclear changes in hepatocytes leading to hepatocytic necrosis and distortion of the portal triad. In the kidneys, higher levels of MOLM led to glomerulonephritis essentially presenting as glomerular oedema leading to reduced Bowman’s space. In the renal tubules, there were protein casts in the tubular lumen. There was a significant difference in gastric pH of the digesta across the treatment groups where controls had lower pH than all the MOLM diets. Bacteriology results, on the other hand, revealed a significant difference in the coliform counts with the controls having the least counts. In the stomach and ileum, higher levels (6 to 12%) of MOLM in the diet led to the submucosal oedema and fat deposition hence increased thickness. In the ileum, high levels of MOLM in the diet led to the hyperplasia of Peyer’s patches. These results imply that, MOLM at lower levels (3% in diet) improves haemoglobin concentration important for oxygen circulation, white blood cell counts, indicating improved innate immunity and hypocholesterolemic properties beneficial in the control of cardiovascular diseases, leading to improved overall productivity of the animals. However, higher levels of MOLM in the diet (>3%) lead to toxicity; distortion of gut morphology, spleen, liver and kidney histo-architecture, that, if fed to the pigs for a prolonged duration may result in organ failure, poor performance and death. Key words: Peyer’s patches, Hepatotoxicity, Renal toxicity, Spleen, Moringa oleifera, Haematology, Growing pigs