V. Ravindran

Massey University

Author Statistics

Papers

Citation

H-Index

i-10 index

Research Field

Avian Liver: The Forgotten Organ

Animals (2019)

F. Zaefarian M.R. Abdollahi A.J. Cowieson V. Ravindran

Despite having huge responsibilities in avian species, published reports on the influence of dietary factors and other possible constraints on the size, development and function of liver are limited. Consideration of the factors that could influence and alter liver function is therefore of critical relevance. In the current review, aspects of liver structure and function, and the influence of feed restriction, anti-nutritional factors, structural components and feed additives on liver are discussed. Effects of feed technology techniques such as thermal treatment and pelleting, feed particle size and whole grain feeding on the liver are also reviewed. A discussion of lipogenesis and lipid storage in poultry is presented to provide a better understanding and to differentiate the normal pathways of lipid metabolism from abnormal (i.e., disordered) pathways. The liver is the main site of fat synthesis in poultry, but under certain conditions, excessive fat can accumulate in the liver and cause problems. Factors contributing to the fatty liver syndrome are also examined.

Lipogenesis

Liver function

10.3390/ani9020063

Cite

Citations (220)

Methodology To Evaluate The Nutritive Value Of Feedstuffs For Poultry And Swine

V. Ravindran

Value (mathematics)

Source

Cite

Citations (0)

Requirement of digestible calcium at different dietary concentrations of digestible phosphorus for broiler chickens 3. Broiler finishers (d 25 to 35 post-hatch)

Poultry Science (2023)

L.S. David M.R. Abdollahi M.R. Bedford V. Ravindran

An experiment was conducted to determine the digestible calcium (Ca) and digestible phosphorous (P) requirements of 25 to 35-day-old broiler chickens. Fifteen corn-soybean meal-based diets containing 2.0, 2.5, 3.0, 3.5, and 4.0 g/kg standardized ileal digestible (SID) Ca and 2.5, 3.5, and 4.5 g/kg SID P were fed to broilers from d 25 to 35 post-hatch. Each experimental diet was randomly allocated to 6 replicate cages (8 birds per cage). Body weight and feed intake were recorded, and the feed conversion ratio was calculated. On d 35, birds were euthanized to collect the ileal digesta, tibia, and carcass for the determination of ileal Ca, and P digestibility, concentrations of ash, Ca, and P in tibia and the retention of Ca and P in the carcass. Titanium dioxide (5.0 g/kg) was included in all diets as an indigestible indicator for the ileal digestibility measurement. Feed intake and total excreta output were measured during the last 4 d of the experimental period for the measurement of apparent total tract retention of Ca and P. Fixed effects of the experiment were dietary concentrations of SID Ca and SID P and their interaction. If the interaction or main effects were significant (P < 0.05), the parameter estimates for second-order response surface model (RSM) were determined using General Linear Model procedure of SAS. The maximum response was not predicted for most of the parameters (including growth performance and tibia) as the Ca effect was linear which indicated that the highest level of Ca employed in the study may have not been high enough. The requirement of dietary SID Ca for maximization of these parameters, therefore, depends on the dietary SID P concentration when the dietary SID Ca is within 2.0 to 4.0 g/kg. However, based on the factorial analysis, the highest weight gain was observed at 3.5 g/kg SID P and 3.5 g/kg SID Ca concentrations. Tibia ash was higher in birds fed 4.5 g/kg SID P and was unaffected by dietary SID Ca concentrations. However, based on overall findings, a combination of 3.5 g/kg SID P and 3.0-3.5 g/kg SID Ca may be recommended for the optimum tibia ash. The recommended SID Ca requirements (at 3.5 g/kg SID P) for weight gain (3.5 g/kg or 6.4 g/kg total Ca) and tibia ash (3.0-3.5 g/kg or 5.5-6.4 g/kg total Ca) are lower than the current Ca recommendations (7.8 g/kg total Ca equivalent to 4.25 g/kg SID Ca; Ross, 2019) for broiler finishers, suggesting possible excess of Ca in diets formulated based on the current recommendation.

10.1016/j.psj.2023.102492

Cite

Citations (4)

Toward standardized amino acid matrices for exogenous phytase and protease in corn–soybean meal–based diets for broilers

Poultry Science (2020)

A.J. Cowieson J.O.B. Sorbara Florian Pappenberger M.R. Abdollahi V. Ravindran

A total of 468 male Ross 308 broilers were used in a digestibility study to determine the additivity of apparent or standardized amino acid (AA) digestibility values for corn, soybean meal (SBM), or a mixture of corn and SBM that were supplemented, or not, with either phytase, protease, or a combination of phytase and protease. These treatments generated a total of 12 experimental diets that were arranged in a 3 × 4 design. A nitrogen-free diet was also fed to estimate endogenous AA loss. Apparent and standardized AA digestibility values were assessed on day 28 posthatch. The apparent digestibility of AA in the complete diet was higher (P < 0.05) than expected based on the digestibility of the corn and SBM individually. However, this overestimation was corrected by the adjustment to standardized values. Importantly, addition of protease or the combination of protease and phytase increased (P < 0.05) the digestibility of AA in corn and SBM. Furthermore, these effects were arithmetically coherent with respect to the measured effects of the enzymes in the mixture of corn and SBM, even improving the additivity of AA digestibility values when assessed on an apparent basis. This study demonstrates that the effect of exogenous protease and phytase on AA digestibility in complete diets is predictable based on measurements made in individual ingredients. In addition to improving digestibility values per se, exogenous protease and phytase may enhance precision in least cost formulation systems.

Phytase

10.1016/j.psj.2019.12.071

Cite

Citations (9)

Effect of limestone particle size and calcium to non-phytate phosphorus ratio on true ileal calcium digestibility of limestone for broiler chickens

British Poultry Science (2016)

Muhammad Naveed Anwar V. Ravindran P.C.H. Morel G. Ravindran A.J. Cowieson

The purpose of this study was to determine the effect of limestone particle size and calcium (Ca) to non-phytate phosphorus (P) ratio on the true ileal Ca digestibility of limestone for broiler chickens. A limestone sample was passed through a set of sieves and separated into fine (<0.5 mm) and coarse (1–2 mm) particles. The analysed Ca concentration of both particle sizes was similar (420 g/kg).Six experimental diets were developed using each particle size with Ca:non-phytate P ratios of 1.5:1, 2.0:1 and 2.5:1, with ratios being adjusted by manipulating the dietary Ca concentrations. A Ca-free diet was also developed to determine the basal ileal endogenous Ca losses. Titanium dioxide (3 g/kg) was incorporated in all diets as an indigestible marker.Each experimental diet was randomly allotted to 6 replicate cages (8 birds per cage) and fed from d 21 to 24 post hatch. Apparent ileal digestibility of Ca was calculated using the indicator method and corrected for basal endogenous losses to determine the true Ca digestibility.The basal ileal endogenous Ca losses were determined to be 127 mg/kg of dry matter intake.Increasing Ca:non-phytate P ratios reduced the true Ca digestibility of limestone. The true Ca digestibility coefficients of limestone with Ca:non-phytate P ratios of 1.5, 2.0 and 2.5 were 0.65, 0.57 and 0.49, respectively.Particle size of limestone had a marked effect on the Ca digestibility, with the digestibility being higher in coarse particles (0.71 vs. 0.43).

10.1080/00071668.2016.1196341

Cite

Citations (45)

Influence of Feed Form on Gizzard Morphology and Particle Size Spectra of Duodenal Digesta in Broiler Chickens

The Journal of Poultry Science (2007)

A.M. Amerah Roger G. Lentle V. Ravindran

We examined gizzard morphology and diet particle size reduction in broiler chickens fed a wheat-based diet that was offered in either a mash or a pelleted form. The pelleted diet had a lower proportion of coarse particles on wet sieving. Birds fed the mash diet had a significantly larger gizzard mass per unit body mass. The gizzards of all birds increased uniformly in size, there being no significant change either in the ratio of content to empty mass or in the ratio of gizzard length to breadth with diet. Thus, there was no tendency for coarse particles to accumulate in the gizzards of bird fed the mash diet. The relative proportion of all classes of particles below 0.500mm was increased and the relative proportion of all particle classes above 0.500mm was reduced in birds regardless of feed form. The relative increase of particles in all classes below 0.500mm was greater in birds fed mash feed. However, digesta exiting the gizzard of birds fed mash diet contained significantly greater amounts of particles of size classes 1mm and greater than digesta of those fed the pelleted diet. Thus, whilst the gizzard operates to generally reduce particle sizes above 0.500mm and increase those below this size, this reduction is not uniform and likely to be a probabilistic function as it is in the human mouth.

Gizzard

Morphology

10.2141/jpsa.44.175

Cite

Citations (36)

Influence of guanidination on apparent ileal amino acid digestibility in some protein sources for broilers

Poultry Science (1998)

V. Ravindran L. I. Hew W. L. Bryden

High pH employed during the guanidination process (conversion of lysine residues to homoarginine) and its possible effects on racemization of amino acid residues to D-forms and on amino acid digestibility are concerns often raised with the use of guanidinated proteins to estimate endogenous amino acid losses in monogastric animals. The objective of the present study was to investigate the influence of guanidination on apparent ileal amino acid digestibility of casein, soybean meal, cottonseed meal, and canola meal for broiler chickens. Apparent ileal digestibility of amino acids in guanidinated and unreacted proteins, with few exceptions, were found to be remarkably similar. These results suggest that the guanidination process has no influence on the susceptibility of proteins to proteolysis and that racemization is not a practical problem when the proteins are guanidinated at low temperatures.

Monogastric

Racemization

10.1093/ps/77.6.873

Cite

Citations (8)

Evaluation of the nutritive value of jackseed (Artocarpus heterophyllus) meal for poultry

The Journal of Agricultural Science (1996)

V. Ravindran G. Ravindran R. Sivakanesan

SUMMARY The starchy seeds of jackfruit ( Artocarpus heterophyllus Lam.) contain 124 g crude protein and 740 g total carbohydrates per kg. The possible replacement value of jackseed meal (JSM) for maize in chick diets was evaluated in Peradeniya, Sri Lanka between 1986 and 1989. In Expt 1, the inclusion of 125 and 250 g raw JSM/kg diet severely depressed growth performance and increased mortality in chicks. Organ weights, relative to body weight, were also affected in chicks fed on diets containing 250 g raw JSM/kg diet. Subsequent analyses revealed lectins and trypsin inhibitors to be responsible for the toxic effects of raw JSM. Processing of JSM by moist-heat treatment completely destroyed these antinutritional factors. This was demonstrated by the results of Expt 2, where the feeding value of processed JSM was found to be comparable to that of maize up to 250 g/kg diet. Moist-heat treatment also improved the in vitro protein digestibility (56·7 v. 84·2%) and apparent metabolizable energy (8·97 v. 13·72 MJ/kg) values of JSM. In Expt 3, the inclusion of 500 g processed JSM/kg diet resulted in reduced broiler performance and lowered the apparent dry matter digestibility and apparent energy utilization of the diets. The non-starch polysaccharide component of the JSM may have been responsible for these negative effects.

Artocarpus

Protein digestibility

10.1017/s0021859600077443

Cite

Citations (3)

Influence of inclusion level of barley in wheat-based diets and supplementation of carbohydrase on growth performance, nutrient utilisation and gut morphometry in broiler starters

British Poultry Science (2019)

W.N.U. Perera M.R. Abdollahi F. Zaefarian T.J. Wester G. Ravindran

1. The influence of barley inclusion level and supplementation of a multi-component non-starch polysaccharide degrading enzyme on performance and nutrient utilisation in broilers was investigated. Normal-starch hulled barley was evaluated with five levels of inclusion (0, 141, 283, 424 and 565 g/kg) in a wheat-based diet and two levels of enzyme supplementation (0 and 150 g/tonne of feed; a 5 × 2 factorial arrangement of 10 dietary treatments). All diets were equivalent in metabolisable energy and digestible amino acid contents. A total of 400, one-d old male broilers (five cages/treatment; eight birds/cage) were used in the experiment.2. Regardless of enzyme supplementation, weight gain (WG) increased up to 283 g/kg of barley and was reduced afterwards (P < 0.01). Increasing levels of barley resulted in greater (P < 0.001) gain per feed (G/F). Enzyme addition increased WG (P < 0.05) and G/F (P < 0.001) at each barley inclusion level.3. Birds fed diets with 0 and 565 g/kg barley showed the lowest and highest (P < 0.001to 0.05) digestibility for all nutrients measured, respectively. Digestibility of all nutrients was improved by enzyme supplementation at each barley inclusion level (P < 0.05). The nitrogen-corrected apparent metabolisable energy improved with increasing inclusion of barley (P < 0.001) and supplemental enzyme (P < 0.01). Increasing inclusion of barley increased the relative weight of gizzard (P < 0.001) and reduced jejunal digesta viscosity (P < 0.001). Supplemental enzyme (P < 0.001) reduced digesta viscosity.4. The optimum inclusion level of barley, with respect to growth performance, was 283 g/kg of diet. Increasing barley inclusion improved nutrient and energy utilisation, possibly through lowered digesta viscosity and better function of the gizzard. Feed efficiency and nutrient and energy utilisation can benefit from carbohydrase supplementation in barley-based diets, regardless of barley inclusion level.

Carbohydrase

Gizzard

Amen

10.1080/00071668.2019.1639142

Cite

Citations (14)

Influence of method of whole wheat inclusion and xylanase supplementation on the performance, apparent metabolisable energy, digestive tract measurements and gut morphology of broilers

British Poultry Science (2004)

Y. B. Wu V. Ravindran David G. Thomas M. J. Birtles W.H. Hendriks

1. The aim of the present study was to examine the influence of whole wheat inclusion and xylanase supplementation on the performance, apparent metabolisable energy (AME), digesta viscosity, and digestive tract measurements of broilers fed on wheat-based diets. The influence of the method of whole wheat inclusion (pre- or post-pelleting) was also compared. A 3 × 2 factorial arrangement of treatments was used with three diet forms (648 g/kg ground wheat [GW], GW replaced by 200 g/kg of whole wheat before [WW1] or after cold-pelleting [WW2]) and two xylanase levels (0 and 1000 XU/kg diet). 2. Birds given diets containing whole wheat had improved weight gains, feed efficiency and AME compared to those fed on diets containing ground wheat. The relative gizzard weight of birds fed WW2 diets was higher than in those fed GW and WW1 diets. Pre-pelleting inclusion of whole wheat had no effect on relative gizzard weight. Post-pelleting inclusion of whole wheat resulted in greater improvements in feed efficiency and AME than the pre-pelleting treatment. 3. Xylanase supplementation significantly improved weight gain, feed efficiency and AME, irrespective of the wheat form used. Viscosity of the digesta in the duodenum, jejunum and ileum were reduced by xylanase addition. Xylanase supplementation reduced the relative weight of the pancreas. 4. Neither xylanase supplementation nor whole wheat inclusion influenced the relative weight and length of the small intestine. 5. Xylanase supplementation increased ileal villus height. A significant interaction between diet form and xylanase was observed for ileal crypt depth. Xylanase supplementation had no effect on crypt depth in birds fed on diets containing GW, but increased the crypt depth in WW2 diets. No significant effects of diet form and xylanase supplementation were observed for the thickness of the tunica muscularis layer of gizzard or villus height, crypt depth, goblet cell numbers or epithelial thickness in the ileum. 6. Improved performance observed with post-pelleting inclusion of whole wheat was associated with increased size of the gizzard and improved AME. The gizzard development hypothesis, however, will not explain the improvements observed with pre-pelleting inclusion of whole wheat, suggesting the involvement of other factors.

Gizzard

Whole wheat

10.1080/00071660410001730888

Cite

Citations (159)