Feed selection and digestibility by captive giraffe

A digestion trial with subsequent examination of feed selection was conducted using two captive giraffe fed four feedstuffs. Apparent digestibility coefficients were relatively high, indicating that the animals were efficiently utilizing the feedstuffs. However, values could be affected by the possible ingestion of soil containing acid-insoluble ash. A high fiber pelleted feed was eaten in a greater quantity than a low fiber feed, even though the constituents in each feed were the same. Gross energy content of residual hay was higher than gross energy content of the offered hay. whereas neutral detergent fiber and acid detergent fiber content were lower in the residual than in the offered hay. The animals did not appear to be selecting for a diet high in energy or low in fiber. Based on these results and other information, re-classification of giraffe as a facultative concentrate selector or as an intermediate feeder may be appropriate.     

13C-n.m.r. studies of monomeric composition and sequence in alginate

High-resolution, ¹³C-n.m.r. spectra of slightly depolymerised alginates have been interpreted. The sequence of monomer units, l-guluronate (G) and d-mannuronate (M), markedly influenced the chemical shifts. At 50 MHz, some of the individual carbon resonances of both units were resolved into four lines, in evident dependence upon the identities of the units immediately preceding and following them in the chains. The relative intensifies of the signals permitted rapid computation of (1) monomeric composition (M/G ratio), (2) monomeric sequence in terms of a complete set of four diad and eight triad frequencies, and (3) the composition (M/G ratio) of end units and of the units adjacent to M-residues at the non-reducing end. The diad frequencies indicated that alginate was a block co-polymer containing number-average, co-monomer block-lengths of ～2?8. The triad frequencies indicated average lengths of ～4?8 for blocks containing two or more units, these being somewhat longer for G- than for M-blocks. Regions of the chains having a strictly alternating sequence of M- and G-residues were short. The relative occurrence of G-centred triads deviated significantly from those predicted by first-order Markovian statistics.