Dears
I want to compare the effect of form of diet (mash, crumble and pellet) on the gene expression and intestinal morphology of broiler but as you know the amount of consumption of these forms of diets are very different specially in early days post hatch. ِDifferent feed consumption will affect intestinal morphology. In your opinion, how can I fix this so I will study the effect of the feed form of intestinal morphology, not quantity of feed consumption.
While you can probably control the weight of feed consumed fairly closely, you need to be aware of some of the unintended consequences of your methodology. Presumably the mash diet will have the lowest consumption rate. Either using a preliminary trial or existing data to estimate predicted daily consumption, you can loosely set your feed allocation levels for the crumble and pellet groups. During the experiment you will need to measure the weight of feed consumed by the mash diet group on a daily basis and be prepared to adjust the feed provided to the crumble and pellet groups accordingly to ensure the weight of feed consumed remains consistent across treatment groups.
I would weigh out slightly less feed for the crumble and pellet groups than you predict the mash group will consume. If you do your feed intake calculation for the mash group every day later in the afternoon, you can then adjust the feed allocation to the crumble and pellet groups to match.
The unintended consequence is that there may be points in the day where no feed is available to the crumble and pellet treatment birds. This could impact feed movement, gut flora (and location of some classes of flora in the fore- mid- or hind-gut), and possibly even intestinal morphology. To get around this you may need to consider adding full-fed control treatments representing the crumble and pellet treatments. You do not have a perfect comparison either way, but at least this way you can start to tease out the impact of feed intake on your measurements.
Reza, I agree with the points made by Dr. Renema. In addition to your attempts to control for the confounding effects of feed form on feed intake and feeding behavior, there is also differences to account for in feed manufacturing. Mash feed requires coarser grind of the grains so as to facilitate handling properties and flow in feeders, whereas pellets and crumbles require feed to be ground finer to achieve optimum pellet agglomeration. Particle size influences gizzard function (larger the better) which slows feed passage and may increase nutrient digestibility. In contrast, the heat processing during conditioning and pelleting may change the chemical nature of the feed components (starch gelatinization, protein-carbohydrate-fat complexes) which could enhance or reduce digestibility. Of course you cannot control everything, but at least control the variables you can so you can focus on better explaining the response you observe from the variables you cannot.
Hi Reza,
I agree with the points made by Dr. Renema and those by Dr. Ferket. In addition to these points, you should also be aware of the inherent presence of enzymes like phytase in your mash diet which would had being heat-destroyed in the pellet and crumble diets. Depending on the types of ingrediets you are planning on feeding, particularly if you would be using wheat and how much, the level of phytase in the mash diet could be high enough to significantly increase nutrient utilization in the birds by itself.
A suggestion is that you treat all the diets (mash, crumble and pellet) the same way. As you will do with your pellet and crumble diets, you can have your mash diet go through the conditioning and heat processes without pelleting (if possible, this is your best way to go around it). A second option is to have the mash diet pelleted as well after conditioning and heating processes and then run through a roller mill with the suitable screen to get it down to the regular mash size. The downside of this second option is that you won`t be having the particle size in your mash diet at regular mash particle size.
Ensuring feeding relatively similar daily intake of each diet and making sure that all your diets go through similar processes will considerably help you take out confounding factors (at least those you can control) and largely limit effects you would observe to diet forms.
One of the best option is to do restricted feeding. 90% of the voluntary feed intake of birds of respective age would make sure similar intakes. You may have to do that on dry matter basis
Dear Abiodun Bello and Seekkuge Susil Priyantha Silva
Thank you for your answers
Best Regards
Dear Vahid
Thank you for answer. Please send me articles that mentioned above (Uni et al.).
Best Regards
Reza Mahdavi Feed consumption by broilers varies with diet form:
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