Matti Näsi

Distillers dried by-products from barley as protein source for ruminants

The nutritive value of barley-derived distillers dried grains (BDDG) and distillers dried grains with solubles (BDDGS) was assessed in digestibility and in sacco rumen degradability experiments. The crude protein contents of BDDG and BDDGS were 26.4 % and 29.9 %, and the crude fibre contents 19.9 % and 17.4 % in DM, respectively. The ADF and NDF contents averaged 33 % and 67 % and the lignin 7.6 % of DM. The digestibilities of the nutrients were measured with four rams in both trials and the distillers by-products were given at two levels, 33 % ad 66 %, in hay-based rations. The digestibilities in BDDG and BDDGS were, respectively, 43.1 °/o and 47.7 % for organic matter, 64.5 °/o and 66.5 % for crude protein, and 86.7 % and 87.9 % for ether extract. Due to the low digestibilities, the energy values of the two products were low, 0.58 FU/kg DM and 8.0 MJ/kg for both, and DCP/FU 295 g for BDDG and 347 g for BDDGS. The rumen degradability of the crude protein of BDDG and BDDGS was found to be low and significantly lower than the degradability of wheat distillery by-products (P < 0.05). Fine grinding gave more rapid degradability. Due to the low total digestibility and reduced lysine content, BDDG and BDDGS may have limited protein availability when given as supplements.

Carboxymethyl cellulose (CMC) whey product as protein source for growing pigs

A digestibility and balance trial was performed with three growing pigs to evaluate the nutritive value and protein utilization of a carboxymethyl cellulose (CMC) whey product used to replace 50 % or 100 % of the dried skim supplement in a barley-based diet. The effect of CMC whey on clinicalchemical blood parameters was also investigated. The CMC whey protein contained 39.6 % crude protein and 36.0 % true protein in DM. The proportion of CMC in the product was 18.3 % of DM. CMC whey had high contents of lysine, cystine, methionine and threonine: 10.3, 2.9, 2.1 and 5.6 g/16 g N, respectively. NFE digestibility was lower on the CMC whey diet than on the skim milk diet (P < 0.05). Faecal excretion of CMC averaged 59.0 %. Protein utilization was effective on the CMC whey diet: 69.9 % of absorbed N was retained. Judging from the blood analyses, the CMC whey product did not have any detrimental effect on the metabolism or health of the pigs. The CMC whey product is well suited as a protein supplement in pig feeding because of its high contents of essential amino acids.