The Influence of Regrinding Coarse Particles from Milled Corn on Mash Properties, Growth Performance and Blood Chemistry in Broilers Chickens

Ghaid J. Al-Rabadi

Abstract


Particle size distribution rather than the average particle size is a more accurate method of specifying feed for animal growth and feed processing. In the feed industry, hammer mill is extensively more used since it is easier to operate and maintain although it produces a broad range of particle sizes and excess of unwanted fines. Thus, an alternative approach to fine milling by hammer mill is needed to avoid the production of unwanted dust-like particles when poultry diet is offered in mash form. This study was conducted to evaluate the effect of grinding coarse particles, after segregation by sieving on: milled corn particle size properties, growth performance, and blood chemistry in broilers during the growing stage. Fifty six Hubbard broilers (3 weeks of age) were randomly allocated into two-dietary treatment groups with seven replicates per treatment and four broilers per replicate. The grower diets were isonitrogenous and isocaloric, but they differed in the level of corn particle size. Corn grains were ground and then sieved to segregate the coarse fraction from the fine fraction. Coarse fraction was then milled again and then mixed with the fine fraction. The two-processing treatments were coded for the influence of corn particle size on diet particle size: Ground Diet (GD) and Reground Diet (RD). The effect of re-milling of the segregated coarse particles and recombining with the fine fraction reduced both the geometric mean diameter (from 1.75 to 0.85mm) and the geometric standard deviation (from 2.14 to 2.01). The effect of re-milling also increased both the particle surface area (from 23.12 to 52.14cm2/gram) and the number of particles per unit mass (from 3350.55 to 16942.60 particles/gram). When compared with GD, RD did not influence the cumulative feed intake, the average daily gain, or the feed conversion ratio. The results showed that the total cholesterol, High Density Lipoprotein (HDL), Low Density Lipoprotein (LDL), and glucose concentrations were not (p>0.05) affected by the dietary particle size. However, both triglyceride and the Very Low Density Lipoprotein (VLDL) concentrations increased (p<0.05) in birds fed RD. It can be concluded from this study that re-milling coarse fraction of corn particle size did not affect broiler growth performance but did not produce excess of fines when diet was offered in mash form.

Keywords


Corn, Particle size, milling, growth performance, blood chemistry, broiler

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