The practice of grazing winter cereals before heading and subsequently harvesting the forage is common in some countries. Triticale (×Triticosecale Wittmack) is particularly interesting due to its nutritional characteristics, and forage yield and quality are strongly influenced by agronomic techniques. The effect of two modes of utilization (cut at heading stage and cut during winter grazing simulation with regrowth cut at heading stage), three nitrogen (N) fertilization levels [0 and 100 kg ha−1 split in two phases; and 100 kg ha−1 before sowing, using a fertilizer with 3,4-dimethylpyrazole phosphate (DMPP) as a nitrification inhibitor (NI)] and mycorrhizal fungus inoculation (mixed inoculation of Glomus intraradices and Glomus moseae) on forage yield and quality, protein fractions and in vitro digestibility of triticale was determined in southern Italy. Mode of utilization and fertilization affected significantly forage yield and quality, while mycorrhizal fungus inoculation influenced positively some quality parameters. Cutting at heading stage of triticale led to high dry matter (DM) production compared to the winter cut simulating grazing, but no differences in protein yield (PY). N fertilization increased total DM and PYs, but no differences were reported among the application modalities of N fertilizers. Triticale protein fractions and protein and fiber digestibility were improved by N fertilization. Mycorrhizal fungus inoculation positively influenced forage quality at heading stage, which resulted in more digestible fiber and protein. As a result, when triticale was grown under Mediterranean conditions, mode of utilization and N fertilization resulted in greater forage yield and quality, while mycorrhizal fungus inoculation influenced positively forage nutritional quality parameters.

Studying the secondary structure of proteins leads to an understanding of the components that make up a whole protein, and such an understanding of the structure of the whole protein is often vital to understanding its digestive behaviour and nutritive value in animals. The main protein secondary structures are the α-helix and β-sheet. The percentage of these two structures in protein secondary structures influences protein nutritive value, quality and digestive behaviour. A high percentage of β-sheet structure may partly cause a low access to gastrointestinal digestive enzymes, which results in a low protein value. The objectives of the present study were to use advanced synchrotron-based Fourier transform IR (S-FTIR) microspectroscopy as a new approach to reveal the molecular chemistry of the protein secondary structures of feed tissues affected by heat-processing within intact tissue at a cellular level, and to quantify protein secondary structures using multicomponent peak modelling Gaussian and Lorentzian methods, in relation to protein digestive behaviours and nutritive value in the rumen, which was determined using the Cornell Net Carbohydrate Protein System. The synchrotron-based molecular chemistry research experiment was performed at the National Synchrotron Light Source at Brookhaven National Laboratory, US Department of Energy. The results showed that, with S-FTIR microspectroscopy, the molecular chemistry, ultrastructural chemical make-up and nutritive characteristics could be revealed at a high ultraspatial resolution (∼10 μm). S-FTIR microspectroscopy revealed that the secondary structure of protein differed between raw and roasted golden flaxseeds in terms of the percentages and ratio of α-helixes and β-sheets in the mid-IR range at the cellular level. By using multicomponent peak modelling, the results show that the roasting reduced (P<0·05) the percentage of α-helixes (from 47·1 % to 36·1 %: S-FTIR absorption intensity), increased the percentage of β-sheets (from 37·2 % to 49·8 %: S-FTIR absorption intensity) and reduced the α-helix to β-sheet ratio (from 0·3 to 0·7) in the golden flaxseeds, which indicated a negative effect of the roasting on protein values, utilisation and bioavailability. These results were proved by the Cornell Net Carbohydrate Protein System in situ animal trial, which also revealed that roasting increased the amount of protein bound to lignin, and well as of the Maillard reaction protein (both of which are poorly used by ruminants), and increased the level of indigestible and undegradable protein in ruminants. The present results demonstrate the potential of highly spatially resolved synchrotron-based infrared microspectroscopy to locate ‘pure’ protein in feed tissues, and reveal protein secondary structures and digestive behaviour, making a significant step forward in and an important contribution to protein nutritional research. Further study is needed to determine the sensitivities of protein secondary structures to various heat-processing conditions, and to quantify the relationship between protein secondary structures and the nutrient availability and digestive behaviour of various protein sources. Information from the present study arising from the synchrotron-based IR probing of the protein secondary structures of protein sources at the cellular level will be valuable as a guide to maintaining protein quality and predicting digestive behaviours.

The effect of protein fractions isolated from cereal grains on the development and survival of the bean weevil, Callosobruchus maculatus, was investigated using wheat, rice and maize. These cereals were fractionated into albumins, globulins, prolamins, glutelins and a residue. The fractions were incorporated in artificial seeds which were infested by C. maculatus. Survival (as indicated by LD50) and development (as indicated by WD50) of 20-day-larvae of the bruchid were negatively affected by most of the fractions. Rice globulins were the most detrimental and affected both the survival and development of the larvae, while wheat albumins and globulins had a stronger effect on larval development than on survival. A previously isolated maize α-amylase/trypsin inhibitor showed an LD50 of 1.5% to Callosobruchus maculatus.