A comparison of ileal digesta and excreta analysis for the determination of amino acid digestibility in food ingredients for poultry.

1. The apparent ileal and excreta digestibilities of amino acids in 15 samples representing 12 food ingredients were determined using 5-week-old male broiler chickens. The ingredients included 3 samples of cereals (wheat, maize and sorghum), 6 samples of plant protein meals (soyabean meal, cottonseed meal, canola meal and sunflower meal) and 6 samples of animal protein meals (meat meal, meat-and-bone meal, feather meal and fish meal). 2. The test ingredients were incorporated as the sole source of dietary protein in assay diets. Each diet was offered ad libitum to 3 pens (4 birds/pen) from d 35 to d 42 post-hatching. Total collection of excreta was carried out during the last 4 d. All birds were killed on d 42 and the contents of the lower half of the ileum were collected. Apparent ileal and excreta amino acid digestibilities were calculated using acid-insoluble ash as the indigestible marker. 3. The influence of site of measurement was found to vary among food ingredients, among samples within an ingredient and among different amino acids within an ingredient. Ileal amino acid digestibility values were similar in some ingredients, but significantly lower or higher in others than the corresponding excreta values. 4. Average ileal and excreta amino acid digestibilities in sorghum and maize were similar, but significant differences were observed for individual amino acids. In contrast, ileal amino acid digestibility values were higher than the corresponding excreta digestibility values in wheat. 5. The average ileal and excreta digestibilites of amino acids in the 3 soyabean meal samples were similar although small, but significant differences were noted for individual amino acids. Site of measurement had no effect on the digestibility of amino acids in canola meal. Digestibilities of valine, isoleucine, phenylalanine, histidine, glutamic acid, alanine and tyrosine in sunflower meal and those of valine, methionine, isoleucine, leucine, lysine, glutamic acid and alanine in cottonseed meal were lower by excreta analysis. 6. Digestibilities in animal protein meals, with the exception of blood meal and fish meal, were consistently higher by excreta analysis. Ileal-excreta differences in individual amino acid digestibilities were more evident in feather meal, meat meal and meat-and-bone meal. 7. Threonine and valine were the indispensable amino acids that were more frequently influenced by the site of measurement. Of the dispensable amino acids, aspartic acid, serine, glutamic acid and alanine were the most affected. 8. Differences determined between ileal and excreta digestibilities in the present study clearly demonstrate that amino acid metabolism by hindgut microflora in chickens may be substantial and that digestibilities measured in the terminal ileum are more accurate measures of amino acid availability than those measured in the excreta.     

Slide Enzyme-Linked Immunosorbent Assay for the Diagnosis of Babesia bigemina Infection in Bovines

A slide enzyme-linked immunosorbent assay (SELISA) for the diagnosis of Babesia bigemina infection in cattle was standardized. Acetone-fixed whole Babesia bigemina-infected erythrocytes on micro-slides were immunoreacted with bovine serum samples followed by antibovine horseradish peroxidase conjugate and developed using diaminobenzidine tetrahydrochloride as a substrate. The positive immunoreactivity (staining pattern) was visualized in the form of dark brown piroplasms. Using the laboratory-standardized SELISA with a sensitivity of 94.4%, the seroprevalence of babesiosis was studied in cattle from two endemic areas of the disease. In comparison to IFAT, SELISA detected higher number of serum samples positive for bovine babesiosis.     

Eclosion blocking effect of ethanolic extract of Leucas aspera (Lamiaceae) on Rhipicephalus (Boophilus) annulatus

The crude ethanolic extract of aerial parts of Leucas aspera was tested for its acaricidal properties against Rhipicephalus (Boophilus) annulatus. The per cent adult mortality, inhibition of fecundity and hatching of laid ova were studied at concentrations of 1.56, 3.13, 6.25, 12.5, 25, 50 and 100mg/ml. Adult tick mortality was significant at the highest concentration tested. Inhibition of fecundity of treated groups differed significantly from control and was concentration dependent. L. aspera extract also produced complete failure of eclosion of eggs from the treated ticks even at lower dilutions of the extract.     

Nutritional value of narrow-leafed lupin (Lupinus angustifolius) for broilers

1. Two experiments were conducted to evaluate the nutritional value of three cultivars (Wallan, Tanjil and Borre) of narrow-leafed lupin (Lupinus angustifolius) for broilers.

2. In Experiment 1, the apparent metabolisable energy (AME) and the apparent ileal amino acid digestibility of the three cultivars were determined. The cultivar effects were not significant for AME and apparent ileal amino acid digestibility coefficients. In general, amino acids in narrow-leafed lupin were well digested, with the notable exception of methionine. Among the indispensable amino acids, arginine had the highest digestibility coefficient (0·92–0·95), while the lowest was for methionine (0·74–0·83).

3. In Experiment 2, using the energy and digestible amino acid values determined in Experiment 1, diets containing 200?g/kg of the three lupin cultivars were formulated and the effects of feeding these diets on the performance and the digestive tract development of broiler starters were investigated.

4. Weight gain, feed intake and feed per gain of broilers fed narrow-leafed lupins diets were similar to those fed on the maize-soy basal diet. The performance of birds fed on diets containing different cultivars of lupins was also similar. Birds fed on lupin diets had similar excreta scores to those fed on the basal diet.

5. Inclusion of 200?g/kg lupins in broiler diets had no effects on the relative weight and length of the intestinal tract. Broilers fed on lupin diets, however, had higher relative weights of liver.

6. These results suggest that narrow-leafed lupins are good sources of protein, but poor sources of AME and sulphur-containing amino acids. It is concluded that, when diets are properly balanced in terms of AME and digestible amino acids, lupins can be included at 200?g/kg inclusion level in broiler starter diets with no adverse effects on performance.     

Effect of feeding diets based on coarse maize on productive performance,gizzard development and energy utilisation of laying hens

1. A total of 2200 White Leghorn layers were used to study the effect of feeding coarse maize on productive performance, gizzard weight, apparent metabolisable energy (AME) and egg quality parameters.

2. The experiment was a completely randomised design with 5 treatments, each being replicated 5 times (88 birds per replicate). Dietary treatments included a control diet with 600 g/kg of ground maize (6 mm sieve) and experimental diets with 150, 300, 450 or 600 g/kg coarse maize (10 mm sieve) replacing (w/w) ground maize. Diets, in mash form, were offered from 39 to 62 weeks of age.

3. Over the entire experimental period, dietary treatments had no effect on any of the production parameters, except on feed intake. A quadratic effect was observed for feed intake, where intake increased at 150 g/kg coarse maize inclusion. At higher inclusion levels of coarse maize, feed intake was similar to that of the control diet. But the differences in daily intake between dietary treatments were only around 1 g/bird and may not be of any biological significance.

4. Dietary treatments had no effect on gizzard weight, AME or egg quality.

5. The results indicate that coarse maize could completely replace maize in layer diets with no adverse effect on egg production, egg quality and dietary energy utilisation. In the current work, although the proportion of coarse particles (over 1 mm) increased with increasing inclusion levels of coarse maize, the differences in the percentage of particles above 1 mm between the fine control (0 g/kg coarse maize) and coarsest (600 g/kg coarse maize) diets was only 15%, and this may limit the value of the findings reported herein.     

Ileal amino acid digestibility assay for the growing meat chicken--comparison of ileal and excreta amino acid digestibility in the chicken

1. The apparent and true amino acid digestibilities in sorghum, wheat, soyabean meal, meat-and-bone meal, fish meal and blood meal for growing meat chickens were determined using an assay based on the collection of digesta from the terminal ileum and comparison was made with digestibility values determined using an excreta-based assay. 2. Five-week-old meat chickens were given maize-soyabean meal basal diet or mixtures of the basal diet and test diets containing the 6 ingredients as the sole source of dietary protein (50:50 on weight basis). Apparent amino acid digestibility values of assay diets at ileal and excreta levels were calculated using chromic oxide as the indigestible marker. True digestibility values were calculated using endogenous outputs determined by feeding a protein-free diet. Amino acid digestibilities of the ingredients were calculated by difference. 3. The site of measurement had no influence on endogenous amino acid output, the exceptions being aspartic acid and glutamic acid. The output of these two amino acids was higher in the excreta. 4. Significant differences were found between ileal and excreta-based digestibility of certain amino acids in some ingredients, with excreta values being usually higher than the ileal values, indicating a net catabolism of amino acids in the large intestine. The degree of net amino acid disappearance was found to be variable among amino acids and ingredients. In general, threonine had the lowest digestibility at the ileal level and, compared with other amino acids, the highest degredation during passage through the hindgut. 5. The results showed that digestibility determination based on excreta collection will overestimate the uptake for some amino acids in some feeds. The degree of overestimation was often considerable, ranging from 8.9% (apparent digestibility of threonine in soyabean meal) to 56% (apparent digestibility of aspartic acid in wheat). It is concluded that digestibility values measured at the terminal ileum provide a more reliable measure of amino acid availability than those measured in the excreta.     

Influence of whole wheat inclusion and a blend of essential oils on the performance, nutrient utilisation, digestive tract development and ileal microbiota profile of broiler chickens

1. The aim of the present experiment was to examine the influence of whole wheat inclusion and a blend of essential oils (EO; cinnamaldehyde and thymol) supplementation on the performance, nutrient utilisation, digestive tract development and ileal microbiota profile of broiler chickens. 2. The experimental design was a 2 × 2 factorial arrangement of treatments evaluating two wheat forms (ground wheat [GW] and whole wheat [WW]; 100 and 200 g/kg WW replacing GW during starter [1 to 21 d] and finisher [22 to 35 d] diets respectively) and two levels of EO inclusion (0 or 100 g/tonne diet). All dietary treatments were supplemented with 2000 xylanase units/kg feed. Broiler starter and finisher diets based on wheat and soybean meal were formulated and each diet fed ad libitum to 6 pens of 8 male broilers. 3. During the trial period (1-35 d), wheat form had no significant effect on weight gain or feed intake. However, WW inclusion tended (P = 0.06) to improve feed per gain. Essential oil supplementation significantly improved weight gain in both diets, but the improvements were greater in the GW diet as indicated by a significant wheat form × EO interaction. 4. Main effects of wheat form and EO on the relative weight, length and digesta content of various segments of the digestive tract were not significant. Significant interactions, however, were found for relative gizzard and caecal weights. Essential oil supplementation significantly increased the relative gizzard weight and lowered relative caecal weight in birds fed on the GW based diet, but had no effect in those fed on the WW based diet. 5. Whole wheat inclusion and EO supplementation significantly improved apparent ileal nitrogen digestibility. Apparent ileal digestible energy was not significantly influenced by the dietary treatments. 6. Ileal microbiota profiling, using denaturing gradient gel electrophoresis, showed that the ileal microbiota composition was influenced by feed form. The mean numbers of bacterial species in the ileal contents of birds fed on the GW diet supplemented with EO tended (P = 0.07) to be higher than those of the ileal contents of birds fed on unsupplemented GW based diet. 7. The present data suggested that dietary addition of EO improves broiler weight gain and ileal nitrogen digestibility both in GW and WW based diets, but that the magnitude of the response to EO for weight gain was greater in GW based diet. Whole wheat feeding was found to be beneficial in terms of feed efficiency.     

Trypsin-sensitive plasmodia in the liver of post-infection rats and rhesus monkeys

Kupffer cells from the liver and erythrocytes from peripheral blood were collected at the post-patent period from albino rats infected earlier with Plasmodium berghei and rhesus monkeys infected earlier with P. cynomolgi var. bastianelli or P. knowlesi. The cells were subinoculated into individual normal recipients. These recipients subsequently showed parasitaemia in their circulation. The parasites present in Kupffer cell preparations were found to be sensitive to trypsin treatment, while those in erythrocytes were found to be resistant to trypsin treatment. This differential sensitivity of parasites to trypsin was observed in all the three species of plasmodia studied so far.     

Replacement of maize with sweet potato (Ipomoea batatas L.) tuber meal in broiler diets

1. The nutrient composition of sweet potato tuber meal (SPM) was similar to that of maize, with the exceptions of crude protein and calcium. The crude protein content was lower (62 v 91 g/kg) and the calcium content was higher (1–9 v 0–1 g/kg) in SPM. The amino acid composition, in general, favoured SPM.

2. Trypsin inhibitor activity, and the contents of oxalate and phytate‐phosphorus in SPM were too low to be of any nutritional concern.

3. The apparent metabolisable energy content of SPM was determined to be similar to that of maize (14–51 v 14–45 MJ/kg).

4. The results of feeding trials showed that SPM can replace up to 400 g/kg maize in broiler diets without adverse effects in performance. The depression in weight gains observed in birds fed on a diet containing 600 g SPM/kg was related largely to lowered food intake arising from the powdery texture of SPM.