G.J. Brisson

The role of folic acid in the nutrition of gestating and lactating primiparous sows

Abstract This experiment aimed to evaluate the folic acid requirements of gestating and lactating gilts. Three groups of gilts received, during gestation, a diet supplemented with either 0, 5 or 15 mg/kg of folic acid. At parturition, each of these groups was subdivided into three subgroups. In each subgroup, the lactation diet was supplemented with 0, 5 or 15 mg/kg of folic acid. The level of folic acid during gestation had no effect on the body weight gain of gilts during gestation but increased linearly ( P ≤ 0.02) the body weight loss during lactation. During gestation and lactation, addition of folic acid increased ( P ≤ 0.05) the concentrations of serum folates. Litter size at parturition and at weaning was not affected by the treatments, although it was numerically higher in sows receiving 15 mg/kg of folic acid during gestation. Milk yield and milk fat, protein and lactose were not influenced by treatments. Concentration of milk folates measured at 1 and 3 weeks of lactation increased ( P ≤ 0.001) with the level of folic acid in the lactation diet; an effect of the gestation treatments was observed at 1 week ( P ≤ 0.001) but had disappeared by the third week of lactation. In piglets, the concentration of serum folates tended to follow the changes observed on milk folates. Growth of piglets and total litter weight from birth to 8 weeks of age increased linearly (P ≤ 0.05) with the level of folic acid in the gestation diet. Therefore, a dietary supplement of 15 mg/kg of folic acid was necessary to avoid the drop in concentrations of serum folates of sows in gestation and seemed to influence some traits of the reproductive performance.

Some functional properties of acetylated and succinylated oat protein concentrates and a blend of succinylated oat protein and whey protein concentrates

Abstract Protein extract from oat groats was acylated to various degrees with acetic and succinic anhydrides to produce acetyl protein concentrate (APC), and succinyl protein concentrate (SPC), respectively. With both the acylating agents, approximately 36% (APC-37, SPC-35) and 76% (APC-76, SPC-76) of the e-amino groups of lysine were acylated, and changes in functional properties were monitored. Size exclusion-HPLC showed some dissociation of oat proteins with acylation. Nitrogen solubility, emulsifying properties, water hydration and fat binding capacities were improved by acylation, and the effect was more pronounced with succinylation. Although the nitrogen solubility of the blend (SPC-76 and whey protein concentrate, 1:1 ratio on protein basis) was slightly lower than that of the whey protein concentrate (WPC), the other functional properties such as emulsifying properties, water hydration, and fat binding capacities were improved in comparison with that of the WPC. The results suggest that acylated oat protein and the blend may serve as a valuable functional ingredient in emulsion food products.

A Study of the Chemical Composition and Nutritive Value of Leaf Protein Concentrates

Abstract Leaf protein concentrates from alfalfa and from clover obtained by solvent-precipitation and by heat-coagulation have been examined for their chemical composition, their nutritive value and their digestibility. The amino acid composition is not affected by the process of precipitation except that solvent precipitation seems to retain more methionine and less leucine than the heat process. Alfalfa and clover have similar amino acid patterns except that alfalfa has more cystine, aspartic acid and serine than clover. The lipids retained with the protein by the heat process contain much more linolenic and less palmitic, stearic, oleic and linoleic acids than those by the solvent process. Acetone retained more linoleic and linolenic acids and less stearic and palmitoleic acids than alcohol. The lipids of clover had more stearic and oleic acids than those of alfalfa. More mineral elements except Na and Fe and more carbohydrates were found in the solvent-precipitated concentrates than in the heat-coagula. Alfalfa protein concentrate was more digestible and had a higher P.E.R. value than clover protein concentrate. Both, however, were inferior to casein. Dispersibility in water was greater for solvent-precipitated than for heat-precipited concentrates.

Dietary supplements of folic acid: blood and growth responses of white veal calves

Abstract The effects of dietary supplements of folic acid on growth performances and haematological and hepatic variables of white veal calves were studied in 90 young dairy calves. From the age of approximately 2 weeks, they received twice daily 0, 4 or 16 mg of supplementary folic acid added to the milk replacer. They were fed exclusively milk replacer for 105 days. Supplements of folic acid increased serum (P⩽0.05) and red blood cell (P⩽0.05) folate concentrations, and slowed the decrease with age of haemoglobin and packed cell volume (P⩽0.05). The addition of 4 or 16 mg of folic acid twice daily to the milk replacer increased hepatic folates by a factor of 39.5% and 57.4%, respectively, as compared to controls (P⩽0.05). Folic acid improved growth (P⩽0.05), but had no effect on feed intake (P>0.05). Time required to reach 180 kg decreased linearly as supplements of folic acid increased (P⩽0.05). Calves receiving 0, 4 or 16 mg of folic acid twice daily reached 180 kg in 95.3±2.7, 89.9±1.l, or 88.7±1.4 days, respectively. It was concluded that dietary supplements of folic acid improved haematological variables and shortened the rearing period of white veal calves without increasing their feed intake.

Rôle de complémentarité des protéines solubles du lait pour un isolat de protéine de soja et pour la caséine en présence de lactose

Abstract The supplementary value of whey protein for a soybean protein isolate was determined in a diet containing 16.5% lactose. Two coprecipitates with different whey protein/casein ratios and containing 4% lactose were also compared on the basis of their nutritive value. The results were evaluated on the basis of growth curves, protein efficiency ratios (PER) and digestibility coeffecients of the protein fraction of the diets. When lactose made up 16.5% of the diet, growth was not affected but protein efficiency decreased.

Selenium in human food stuffs collected at the Ste-Foy (Quebec) food market

Abstract Selenium was estimated in 101 duplicate food samples collected randomly at the local food stores in the Ste-Foy, Que. area. Considerable variations in the selenium content of the various food samples with little differences between duplicates were observed. Seafood (0.588 μ g/g), meat (0.588 μ g/g, excluding kidneys), cereal products (0.363 μ g/g) and some vegetable foods namely asparagus (0.860 μ g/g), garlic (0.300 μ g/g), fresh mushrooms (0.298 μ g/g), cauliflower (0.262 μ g/g) and eggplant (0.133 μ g/g) were the richest foodstuffs containing selenium. Other vegetables (0.014 μ g/g), dairy products (0.025 μ g/g) and fruits (0.009 μ g/g) contained very small amounts of the essential element. Preserved foodstuffs (with the exception of mushroom) tended to contain less selenium than fresh raw foods. The differences, however, were not statistically significant.

Effect of methanol/acetone/water extraction and enzymatic hydrolysis on the nutritional value of unheated rapeseed proteins

The objective of this work was to study the effect of the extraction of phenols by methanol/acetone/water and proteolysis (pepsin 1 hour; trypsin 2 hours) on the nutritional characteristics of unheated rapeseed protein as measured by weight gain, protein intake, net protein ratio, apparent digestibility and absorbed protein. The effect of proteolysis of the methanol/acetone/water extracted rapeseed protein, and the effect of mixing the methanol/acetone/water extract back with the extracted rapeseed protein was also studied. Extraction of phenolic compounds from rapeseed flour significantly improved weight gain, protein intake, net protein ratio and absorbed protein value. However, the mixing of phenolic extract with the extracted rapeseed protein did not appear to have a significant effect.Enzymatic hydrolysis (1 hour with pepsin and 2 hours with trypsin) of the raw material significantly improved the weight gain and protein intake. The combined methanol/acetone/water extraction and protein hydrolysis treatments were beneficial on all nutritional quality parameters of rapeseed protein. These results suggest that the protein-bound phenolic compounds, rather than the free phenolic compounds contribute mainly to the decrease in the nutritional values of proteins associated with phenolic compounds in raw flour before extraction.

The enigma of the trans fatty acids

Margarines and shortenings, man made equivalents of butter and lard, contain different amounts of partially hydrogenated vegetable oils. As described in the preceding chapter, the partial hydrogenation of vegetable oils, such as corn and soybean, modifies the chemical and physical properties of their fatty acids. Partial hydrogenation, for example, transforms some fatty acids into new compounds called fatty acid isomers. We have already distinguished between positional and geometrical isomers of unsaturated fatty acids in Chapter 1. Geometrical isomers are illustrated in Fig 3 in which it is seen that the cis-isomers are curved at the point of unsaturation, while the trans-isomers are linear. The natural vegetable oils contain only cis-isomers, while the partially hydrogenated oils contain variable amounts of trans-isomers.

Saturated and polyunsaturated fats

Dietary fats consist of mixed triglycerides which are formed by the esterification of glycerol with saturated and unsaturated fatty acids (See Chapter 1). Fats are said to be saturated if they contain a sizable proportion of saturated fatty acids, as compared with unsaturated fats which are rich in unsaturated fatty acids. Fats of animal origin are generally considered to be saturated and fats of vegetable origin unsaturated. The two types of fat contain both saturated and unsaturated fatty acids but the ratios differ in each class.

The technology of edible fats and oils

The consumption of fats by Canadians has remained practically constant since 1950, varying only by 6–10 per cent over the years and settling at about 25 kilograms per capita since 1970. The nature of the fats consumed, however, has changed (Fig 17). The consumption of butter, for example, fell by 50 per cent between 1950 and 1975, whereas that of margarine increased by 70 per cent and that of shortenings and shortening oils by 86 per cent1.