Besides mucking about with the straw business, I've been quite busy with the actual working parts of the latest feeding trial. Last Sunday, I collected about 10 g of fresh excreta from each pen. On Monday, we sacrificed one chicken from each pen. We collected the digesta from the lower part of their small intestines. This involved removing the GI tract from the esophagus to the cloaca, including the liver, pancreas, gall bladder, and spleen, which are pretty much integrated with the intestines, weighing the whole mess then pulling it all apart and cutting out the lower part. I then squeezed the contents of the lower part into plastic vials, sort of like gently squeezing stuff out of a long, cooked ziti pasta. We want to look at the digesta and the excreta because we want to know if the enzyme we are adding is helping the chickens digest the whole flaxseed better. That is, we want to know how much of their diet is just passing through and how much of it are they actually incorporating. If the enzyme is helping them digest the flaxseed, we should see that reflected in their digesta and excreta, and we should expect to see an increase in beneficial fatty acids in their tissues at the end of the trial.
Collecting the excreta turned out to be no big deal. Chickens fed these kinds of special diets don't have poop that looks like what the blue jay shat onto your car windshield two days ago. These broiler chickens poop out sticky turd-shaped poops. It doesn't smell all that bad either. Sure, if they keep shitting on the same litter for months and months, the ammonia smell will increase but remember that broilers are sacrificed at 6 weeks of age. Plus, after years of owning dogs, I'm not terribly wound up about poop. Well, that's not true. I'm rather interested in it but I'm not afraid of it or squicked out by it.
Then on Tuesday, we mixed the second-stage diets, 100 lbs each of four diets. That basically involves me weighing each 100 lbs out in 3-pound-scoop increments. Good for toning the arms. We make the diets ourselves by mixing calculated amounts of ground corn, wheat middlings, soybean meal, canola oil, flaxseed, and extra vitamins and things such as salt, calcium, amino acids. We have to weigh the remnants of the first-stage diet, emptying all the feeders, then refill them with a weighed amount of the new diet. Lots of scooping and weighing and hauling buckets from one end of the barn to the other. It's hot, dusty, physical work. By the end of feed mixing days, I am covered from head to toe in a fine, pale dust. It takes two wash cycles to get my clothes clean.
Today, I started analyzing the digesta samples. The dry matter determination involves weighing the samples out then drying them in an oven. Oddly, they smelled kind of sweet, a lot like the whole grain bread that I eat. I'll do the same procedures on the excreta tomorrow. I am afraid to even speculate what chicken poop will smell like when it is drying in the oven! I don't think it will smell like whole grain bread. Those gut bacteria have had their way with things once the food is turned into excreta.
I'm pretty pleased with my advisor's management style. She prints up protocols for sample collection and analysis procedures, shows me how to do lab procedures once all the way through then simply turns me loose to sort it out myself. I have made some mistakes but none that are costly in terms of data or equipment. Two weeks ago, I had a bunch of unexpected and unwanted null results. After thinking about it for a day, I devised a set of three sensitivity tests to figure out what I was doing wrong. Using those tests, I isolated the problem and I expect to be back on track with those analyses quickly. I'm glad that she is letting me flail around a bit--she's busy and can't micromanage me but I don't think that's her style anyway. It is working out well between us.
On top of all of this excitement, I have set a goal that I must read at least two papers every day, summarize them, and get the information into my thesis draft. I plan to have the literature review/introduction done by the end of the summer. So far, so good. The thesis draft is 32 pages long (1.5-line spacing with section headings but otherwise unformatted) and I've read and incorporated half of the more than 100 references I've collected to date. I keep having to dig up new references though, especially when I need to get a primary source (in that case, those are actually the older papers). "John said that Mary said that this is so" doesn't work when writing a thesis (or dissertation). You need to try to get Mary's original paper to find out what she said. I add two or three new papers for every half dozen that I read. But I know from experience that this will slow down as I start to hone in on the most important concepts.
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