Effects Of Different Dietary Concentrations Research Articles

Influence of different concentrations of chia (Salvia hispanica) and flaxseed (Linum usitatissimum) meal on fillet fatty acid profile of Nile tilapia (Oreochromis niloticus)

The nutritional quality of tilapia fillet is characterized by low omega-3 polyunsaturated fatty acids (n-3 PUFAs). The objective of the present study was to evaluate the effect of different dietary concentrations of chia (Salvia hispanica) and flaxseed (Linum usitatissimum) meal on the omega-3 fatty acid content of tilapia (Oreochromis niloticus) fillet. Six experimental diets incorporating 5, 10, and 15% chia or flaxseed meals, respectively, were given to the fish (238.36 ± 7.61 g, initial weight) for 45 days before harvesting. The α-linolenic acid (ALA) and n-3 PUFA contents in the fillet differed significantly among diets (P < 0.05). Diets containing 15% chia or flaxseed meal had the highest concentrations of ALA (4.80 and 4.75%, respectively) and n-3 PUFA (13.65 and 15.92%, respectively). Thus, chia or flaxseed meal dietary inclusion increased the ALA and n-3 PUFA contents in the tilapia fillet. Chia or flaxseed meals are useful and potential alternatives to improve the nutritional value of O. niloticus fillets.

Role of the glutathione redox system in the susceptibility of pheasants (Phasianus colchicus) to ochratoxin A.

The purpose of the present study was to investigate the effects of different dietary concentrations of ochratoxin A (OTA) on the growth, feed intake, mortality, blood plasma protein content and some parameters of lipid peroxidation and the glutathione redox system of pheasant chicks in a three-week long trial. A total of 320 seven-day-old female pheasants were randomly assigned to four treatment groups (n = 40 in each), fed with a diet artificially contaminated with OTA [control (<0.02 mg/kg), 0.88 mg/kg, 1.14 mg/kg and 1.51 mg/kg] for 21 days (up to 28 days of age). The pheasant chicks were sacrificed at early (12, 24 and 72 h) and late (7, 14 and 21 days) stages of mycotoxin exposure to check the effect of OTA. Minimal feed refusal was found in the medium- and high-dose toxin groups (-9.8 and -7.9%, respectively), and body weight gain was nearly the same in all groups. The glutathione redox system was activated mainly in the liver, confirmed by significantly increased reduced glutathione content and glutathione peroxidase activity during the late phase of mycotoxin exposure and at a high-dose treatment. The results suggest that pheasants have low susceptibility to OTA, and activation of the glutathione redox system has importance in this tolerance.

Role of glutathione redox system on the susceptibility to deoxynivalenol of pheasant (Phasianus colchicus)

There are only a few reports on the effects of mycotoxins on pheasant (Phasianus colchicus) and the susceptibility to deoxynivalenol of these birds have never been reported before. The present experiment focuses to investigate the effects of different dietary concentrations of deoxynivalenol on blood plasma protein content, some parameters of lipid peroxidation and glutathione redox system and on the performance of pheasant chicks. A total of 320 1-day-old female pheasants were randomly assigned to four treatment groups fed with a diet contaminated with deoxynivalenol (control, 5.11 mg/kg, 11.68 mg/kg and 16.89 mg/kg). Birds were sacrificed at early (12, 24 and 72 h) and late (1, 2 and 3 weeks) stages of the experiment to demonstrate the oxidative stress-inducing effect of deoxynivalenol. Feed refusal was dose dependent, especially in the last third of the trial, but only minor body weight gain decrease was found. Lipid-peroxidation parameters did not show dose-dependent effect, except in blood plasma during the early stage of the trial. The glutathione redox system, reduced glutathione content and glutathione peroxidase activity, was activated in the liver, but primarily in the blood plasma. Glutathione peroxidase activity has changed parallel with reduced glutathione concentration in all tissues. Comparing our results with literature data, pheasants seem to have the same or higher tolerance to deoxynivalenol than other avian species, and glutathione redox system might contribute in some extent to this tolerance, as effective antioxidant defence against oxidative stress.

The effect of Goji berries (Lycium barbarum) dietary supplementation on rabbit meat quality

This study evaluated the effect of different dietary concentrations of Goji berries (GB) on the meat quality of rabbit. At weaning, 60 New Zealand male rabbits were assigned to three groups and fed with a commercial standard diet (C), C supplemented with 1% (LG) or 3% Goji berries (HG) until slaughter. Supplementation did not affect colour, water holding capacity, and tenderness but regression analyses showed linear relationships between pH (P < .05), Thiobarbituric Acid Reactive Substances (TBARS; P < .001), Oxygen Radical Absorbance Capacity (ORAC; P < .001), Redox Index (RI; P < .001), and phenolic content (P < .001) of Longissimus thoracis et lumborum muscle and the rate of GB in the feed. However, by pairwise comparisons emerged that acidification (pH: P < .05), antioxidant/oxidant status (TBARS, ORAC, RI; P < .001), and phenolic content (P < .01) of muscle significantly improved only in HG compared with C group. Then, a dose-dependent relation was found but only the higher dose of GB guaranteed an increase in protection against oxidative phenomena of meat.

Role of Glutathione Redox System on the T-2 Toxin Tolerance of Pheasant (Phasianus colchicus)

The purpose of the present study was to evaluate the effects of different dietary concentrations of T-2 toxin on blood plasma protein content, lipid peroxidation and glutathione redox system of pheasant (Phasianus colchicus). A total of 320 one-day-old female pheasants were randomly assigned to four treatment groups fed with a diet contaminated with different concentrations of T-2 toxin (control, 4 mg/kg, 8 mg/kg and 16 mg/kg). Birds were sacrificed at early (12, 24 and 72 hr) and late (1, 2 and 3 weeks) stages of the experiment to demonstrate the effect of T-2 toxin on lipid peroxidation and glutathione redox status in different tissues. Feed refusal and impaired growth were observed with dose dependent manner. Lipid-peroxidation was not induced in the liver, while the glutathione redox system was activated partly in the liver, but primarily in the blood plasma. Glutathione peroxidase activity has changed parallel with reduced glutathione concentration in all tissues. Based on our results, pheasants seem to have higher tolerance to T-2 toxin than other avian species, and glutathione redox system might contribute in some extent to this higher tolerance, in particular against free-radical mediated oxidative damage of tissues, such as liver.

Effect of different dietary concentrations of Amino Acids on the performance of two different Broiler Strains

Four Nutritional Programs (NP) used in the Brazilian poultry industry were tested in two broiler strains (Cobb 500 and Ross 308). NP varied in the concentrations of their main essential amino acids (AA) and were classified as Low, Regular, High and Mixed (high AA concentrations up to 21 days and regular concentrations after that). Minimum digestible Met+Cys/Lys, Thr/Lys, Arg/Lys, Ile/Lys, and Val/Lys ratios were 0.74, 0.64, 1.05, 0.65 and 0.75, respectively, in all NP, and no minimum amount of CP was fixed. There were no interactions between strain and NP for any of the evaluated responses. From 1 to 47 days of age, birds fed the Low NP presented lower average body weight and body weight gain (BWG). The high NP allowed for better feed conversion ratio (FCR), followed by the Regular and the Mixed NP. Ross 308 broilers were heavier, presenting worse FCR due to higher FI. Birds fed the High NP had lower carcass yield than those fed the Low NP. The Low and Regular NP had lower costs per WG when compared with the High NP. Low and Regular NP presented higher gross margin returns compared with the High NP. The Regular and Mixed NP are the most recommended, presenting intermediate performance and higher economic returns.

Digestive enzyme activity in juvenile Nile tilapia (Oreochromis niloticus, L) submitted to different dietary levels of shrimp protein hydrolysate

The effect of different dietary concentrations of shrimp protein hydrolysate (SPH) on digestive enzyme activity of Nile tilapia juveniles was evaluated. SPH concentrations in diets were 0, 15, 30 and 60 g kg−1 (treatments SPH0, SPH15, SPH30 and SPH60, respectively). Hemoglobin, azocasein, BApNA (Nα-benzoyl-dl-arginine-p-nitroanilide), SApNA (Suc-Ala-Ala-Pro-Phe p-nitroanilide), aminoacyl of β-naphthylamide and starch were used as substrates for enzyme activity determinations. The activity of total alkaline protease was significantly higher (P < 0.05) in fish under SPH15 and SPH60 treatments than in the control (SPH0). However, the effect was not dose-dependent. Substrate-SDS-PAGE was also performed to evaluate changes in the profile of Nile tilapia digestive proteases caused by SPH. Substrate-SDS-PAGE revealed 12 active proteolytic bands, eight of which responded to SPH dietary incorporation. Inhibition substrate-SDS-PAGE indicated a decrease in the activity of three enzymes, with trypsin activity decreasing with the increase of SPH concentration, whereas the opposite occurred for two aminopeptidases. Distinct protease profiles were also found for each treatment, suggesting adaptability of digestive proteases from Nile tilapia to the different diets.

A randomized trial of DHA intake during infancy: School readiness and receptive vocabulary at 2–3.5 years of age

BackgroundStudies investigating the effects of docosahexaenoic acid (DHA) in infant formula on language development yield conflicting results. No study to date has investigated the effects of DHA in infant formula on school readiness. AimTo determine the effects of different dietary concentrations of DHA provided during the first 12months of life on language development and school readiness. DesignThis was a double-masked, randomized, controlled, prospective trial. A total of 182 infants were enrolled at 1–9days of age and assigned randomly to receive infant formula with one of four levels of DHA: control (0% DHA), 0.32% DHA, 0.64% DHA, or 0.96% DHA. All formulas with DHA also contained 0.64% arachidonic acid. One hundred forty-one children completed the 12-month feeding trial and were eligible for this study. Consent was obtained from 131 participants. School readiness was assessed at 2.5years using the Bracken Basic Concept Scale—Revised (BBCS-R) and receptive vocabulary was assessed at 2 and 3.5years using the Peabody Picture Vocabulary Test—Third Edition (PPVT-III). ResultsThere were no diet group differences on any of the BBCS-R subscales. On the PPVT-III, the control group had higher raw scores and standard scores than both the 0.32% and 0.96% groups at 2years of age. These differences were not evident at 3.5years. ConclusionsDietary DHA during the first year of life did not enhance school readiness or language development. Children who consumed infant formula with 0.32% and 0.96% DHA showed lower receptive vocabulary scores than controls at 2 but not 3.5years of age.

Comparison of effects of dietary coconut oil and animal fat blend on lactational performance of Holstein cows fed a high-starch diet

Dietary medium-chain fatty acids (C8:0 through C12:0) are researched for their potential to reduce enteric methane emissions and to increase N utilization efficiency in ruminants. We aimed to 1) compare coconut oil (CNO; ∼60% medium-chain fatty acids) with a source of long-chain fatty acids (animal fat blend; AFB) on lactational responses in a high-starch diet and 2) determine the effect of different dietary concentrations of CNO on dry matter intake (DMI). In experiment 1, the control diet (CTRL) contained (dry basis) 40% forage (71% corn silage, and alfalfa hay and haylage), 26% NDF, and 35% starch. Isonitrogenous treatment diets contained 5.0% of AFB (5%-AFB), CNO (5%-CNO), or a 1-to-1 mixture of AFB and CNO (5%-AFB-CNO) and 0.8% corn gluten meal in place of corn grain. Thirty-two multiparous dairy cows (201±46 d postpartum; 42.0±5.5 kg/d 3.5% fat-corrected milk yield) were adapted to CTRL, blocked by milk yield, and randomly assigned to 1 of 4 treatment diets for 21 d with samples and data collected from d 15 through 21. Treatment 5%-CNO decreased DMI markedly and precipitously and was discontinued after d 5. In wk 3, 5%-AFB and especially 5%-AFB-CNO lowered total-tract NDF digested vs. CTRL (2.6 vs. 1.8 vs. 3.1 kg/d, respectively), likely because fat treatments reduced DMI and 5%-AFB-CNO impaired total-tract NDF digestibility. Milk fat concentrations were 3.10% (CTRL), 2.51% (5%-AFB), and 1.97% (5%-AFB-CNO) and correlated negatively to concentrations of C18:2 trans-10,cis-12 in milk fat. Additionally, 5%-AFB and 5%-AFB-CNO tended to lower milk yield and decreased yields of solids-corrected milk and milk protein compared with CTRL. Fat treatments decreased milk lactose concentration, but increased milk citrate concentration. Moreover, cows fed 5%-AFB-CNO produced less solids-corrected milk than did cows fed 5%-AFB. In experiment 2, diets similar to CTRL contained 2.0, 3.0, or 4.0% CNO. Fifteen multiparous cows (219±42 d postpartum; 42.1±7.0kg milk yield; mean ± SD) were blocked by DMI and randomly assigned to 1 of 3 treatment diets for an 8-d evaluation. Dietary concentration of CNO affected DMI, with the greatest depression at 4.0% CNO. Overall, dietary CNO depressed DMI and NDF digestibility of a high-starch diet compared with AFB. Feeding CNO to lactating cows equal to or greater than 2.5% decreased lactational performance or DMI.

Effect of different dietary concentrations of inorganic and organic copper on growth performance and lipid metabolism of White Pekin male ducks

1. The effect of different dietary concentrations of inorganic and organic copper on performance and lipid metabolism of White Pekin ducks (WPD) was investigated from 1-49 d of age. A common basal diet was supplemented with 4, 8, 12 and 150 mg/kg of copper (Cu) from inorganic and organic sources to obtain 9 treatments, including 4 concentrations of Cu x two sources, and the unsupplemented control group. Each treatment contained 5 replicates of 9 male ducks each. 2. Supplementation of Cu at 8 mg/kg in inorganic form was adequate for growth of male WPD from 1-56 d of age. Inorganic Cu significantly decreased feed intake and improved feed conversion ratio, compared with the organic form. 3. Plasma Cu significantly increased, while plasma Zn significantly decreased, due to Cu supplementation. Organic Cu showed better efficacy than inorganic for improving liver Cu concentration, Cu excretion and apparent Cu retention. 4. Dietary Cu concentration significantly affected percentage blood and Hgb and abdominal fat deposition. In addition, inorganic Cu increased percentage blood and abdominal fat deposition compared with the organic source. 5. Supplementation of 150 mg/kg of Cu significantly decreased liver and meat lipids, cholesterol, and colour and tenderness of meat; while liver protein and moisture was increased. In addition, dietary 150 mg/kg of Cu supplementation significantly decreased plasma lipids, triglycerides and cholesterol, while increasing plasma AST and ALT. 6. Organic Cu was more potent for decreasing plasma triglycerides than the inorganic source. However, plasma cholesterol was only significantly decreased with the inorganic source of Cu, compared with the unsupplemented control. 7. The organic Cu was safer as a feed additive for WPD, especially at the lower concentrations up to 12 mg; while some mild to moderate changes may be developed at the higher doses, when fed at pharmacological concentrations as a growth promoter.

Effect of different dietary concentrations of brown marine algae (Sargassum dentifebium) prepared by different methods on plasma and yolk lipid profiles, yolk total carotene and lutein plus zeaxanthin of laying hens

The effect of different concentrations (0%, 3% and 6%) of brown marine algae (BMA, Sargassum dentifebium) prepared according to different methods (sun-dried, SBMA; boiled, BBMA; autoclaved, ABMA) on plasma and yolk lipid profiles, carotene, and lutein plus zeaxanthin in egg yolks was studied in hens aged from 23 to 42 weeks (30 hens per treatment). We determined the fatty acid profiles in BMA and in the egg yolk of hens fed different levels of BMA prepared according to different methods. In addition, plasma and yolk lipid profiles, yolk total carotene, and lutein plus zeaxanthin were determined at week 42 of age. Plasma and yolk cholesterol were significantly lower in groups fed diets containing either 3% or 6% BMA than in the control group, but high-density lipoprotein (HDL) significantly decreased as BMA concentration increased. There was a significant similar decline in yolk triglycerides with inclusion of either 3% or 6% BMA in the laying hen diet. Palmitic acid was the main saturated fatty acid (SFA) found in BMA and oleic acid (omega-9) and linoleic acid (omega-6) were the main unsaturated fatty acids (UFA), while there was a significant increase in palmitic acid in egg yolk when BMA was included at 6%. There was a significant increase in oleic acid (omega-9) when feed containing 3% BMA was given compared to the control group, but this decreased with a further increase in BMA. Linoleic acid (omega-6) also significantly decreased with inclusion of either 3% or 6% BMA. There was a significant increase in total carotene and lutein plus zeaxanthin in the laying hen eggs as a result of feeding diets containing 3% and 6% BMA.

Effects of natural zeolite (clinoptilolite) on eggshell quality

Using inorganic additives is one suggested approach for improvement of performance or for preventing some disorders and poisoning of farm animals. One of those which use in animal diets is zeolite. There are more than 40 types of natural zeolites, of which one of the commonest is Clinoptilolite. Clinoptilolite has a relatively constant crystalline structure and has good adsorption properties. One of the most important problems in the poultry industry is low eggshell quality, particularly at end of lay. This leads to problems such as the breaking of egg in transport. Research on this has indicated positive effects of zeolites. Adding 1.5% clinoptilolite causes a significant increase in the calcium CA concentration of serum (Hossein et al., 1994). Olver (1989) observed a significant increase in eggshell thickness when 5% clinoptilolite was added to the diet of laying hens. The purpose of present study was to investigate the effect of different dietary concentrations of clinoptilolite on some blood parameters and eggshell quality.

Effects of Florfenicol and Chromium (III) on Humoral Immune Response in Chicks

One hundred and sixty day-old Hainan chicks were randomly allotted into eight pens to investigate the effect of different dietary concentrations of chromium (Cr) in the form of chromium chloride, and different dosages of florfenicol on humoral immune responses by determining antibody titers to Newcastle disease (ND) vaccines using the hemagglutination inhibition test. The results indicated that ND antibody titers were significantly higher in chicks receiving Cr at low (5 mg/kg feed) and middle (10 mg/kg feed) dose compared with the control (p 0.05), but the ND antibody titers were significantly decreased in chicks receiving 200 and 400 mg/kg feed of the drug (p<0.01). The ND antibody titers of group receiving 200 mg/kg feed of florfenicol plus 10 mg/kg Cr were slightly higher than that of the group receiving single florfenicol of 200 mg/kg although, no significant differences were observed between these two treatments. It is suggested that the humoral immune response impaired by florfenicol (200 mg/kg feed) could not be significantly reversed by Cr (10 mg/kg feed). (Asian-Aust. J. Anim. Sci. 2004. Vol 17, No. 3 : 366-370)

Optimal dietary concentration of vitamin E for alleviating the effect of heat stress on egg production in laying hens

1. The effects of different dietary concentrations of vitamin E (alpha-tocopherol acetate) were investigated on laying hens exposed to chronic heat stress at 32 C from 26 to 30 weeks of age. 2. Diets containing 5 dietary concentrations of vitamin E (a control diet containing 10 mg alpha-tocopherol/kg or this diet supplemented to contain 125, 250, 375 and 500 mg alpha-tocopherol/kg) were fed to 335 birds. Half of the birds received the supplemented diets for only 4 weeks before the heat stress period (short supplementation duration, SSD) and were fed on the control diet for a further 12 weeks. The remaining birds were fed on the supplemented diets throughout the experiment, 4 weeks before, 4 weeks during and 8 weeks after the heat stress period (long supplementation duration, LSD). 3. Egg production was significantly higher during (80.6 vs 68.9%, P <0.02) and after (75.3 vs 62.7%, P <0.02) the period of stress in the LSD group fed on the diet containing 250 mg vitamin E/kg compared with the group fed on the control diet. LSD birds given 375 and 500 mg vitamin E/kg also had higher egg production than control birds during heat stress but the differences failed to reach significance (74.6 vs 68.9% and 77.1 vs 68.9% respectively). In the SSD groups, mean egg production of the birds given the diets supplemented with 125 mg vitamin E/kg or more was significantly different from the control group after heat stress (70.3 vs 62.7%, P <0.05). Egg weight and food intake were similar in all the groups. 4. Plasma and liver vitamin E concentrations were proportional to the vitamin E intake before the stress period, dropped during heat stress in the SSD groups but were maintained at concentrations closer to those observed before heat stress in the LSD groups. 5. It is concluded that a dietary supplement of 250 mg vitamin E/kg provided before, during and after heat stress is optimum for alleviating, at least in part, the adverse effects of chronic heat stress in laying hens.

Effect of different dietary concentrations of spray-dried porcine plasma and a modified soyprotein product on the growth performance of piglets weaned at 6 kg body weight

A total of 180 weaned pigs (initially 6.2 kg body weight and 22 days of age), and divided into three treatment groups, was used to determine if it is possible to substitute, partially or totally, spray-dried porcine plasma (SDPP) for a modified soyprotein product (MSP) (550 g kg −1 crude protein) from 0 to 14 days post-weaning. From 0 to 14 days after weaning, pigs were fed with iso-proteic, and iso-energetic feeds, containing 60 g kg −1, 30 g kg −1 or 0 g kg −1 SDPP and 0 g kg −1, 50 g kg −1 or 100 g kg −1 modified soyprotein, respectively. All pigs were fed a common starter feed, (containing 11.9 g kg −1 lysine) from 15 to 40 days post-weaning. Pigs fed 60 g kg −1 SDPP gained weight faster (from 0 to 14 days on trial) than pigs in other treatment groups ( P<0.01). Pigs fed 30 g kg −1 SDPP grew faster than pigs fed 100 g kg −1 modified soyprotein ( P<0.05). Pigs fed SDPP from 0 to 14 days on trial had a better average weight gain ( P<0.05) for the entire trial period (0 to 40 days). From 0 to 7 days, pigs fed diets containing 60 g kg −1 SDPP ate more than pigs in the other two treatment groups ( P<0.01), and pigs fed 30 g kg −1 SDPP ate more than those given the diet with 100 g kg −1 modified soyprotein ( P<0.05). From 8 to 14 days on trial, pigs fed the diet containing 60 g kg −1 SDPP ate more than pigs in the other treatments ( P<0.01) and no differences were observed between the other two treatments. Pigs which had been fed SDPP in the pre-starter period had better feed intake ( P<0.05), and had the best feed efficiency ( P<0.01) from 0 to 40 days on trial. Analysis of productive parameters indicated that SDPP had a positive effect on growth performance with respect to modified soybean meal but that partial replacement of SDPP with modified soybean offers an economic advantage.

Influence of high dietary vitamin E supplementation on egg production and plasma characteristics in hens subjected to heat stress

1. The effects of different dietary concentrations of vitamin E (alpha-tocopherol acetate) were investigated in 2 experiments on laying hens exposed to chronic heat stress at 32C. 2. In the first experiment, egg production and plasma concentrations of calcium and egg yolk precursors were measured in 24 hens before, during and after a stress period of one week and fed on diets containing 10 or 500 mg vitamin E/kg. 3. In the second, larger experiment, egg production and food intake were measured in 300 hens housed in 2 temperature-controlled rooms and fed on diets containing 10, 125 or 500 mg vitamin E/kg. Birds in room 1 were stressed from 24 to 28 weeks of age and those in room 2 from 32 to 36 weeks. 4. In experiment 1, egg production and egg weight were significantly higher (72.6 vs 51.2%, P < 0.05 and 66.6 vs 63.1 g, P < 0.005 respectively) during and after the period of stress in the group given 500 mg vitamin E/kg. Plasma concentrations of calcium, vitellogenin (zinc) and VLDL (triglyceride) were also higher in this group. 5. In experiment 2, egg production was significantly higher (65.4 vs 56.2%, P < 0.05) during and after the period of heat stress in birds in room 1 fed on the diet containing 500 mg vitamin E/kg. Egg production was also higher (49.9% vs 44.7%) on this treatment during the stress period in room 2, though the difference was not significant (P < 0.10). Egg weight and food intake were unaffected by treatment in either room. 6. It is concluded that dietary supplementation with extra vitamin E can, at least in part, alleviate the adverse effects of chronic heat stress in laying hens, perhaps by maintaining the supply of egg precursors in plasma.

Dietary phosphorus and food allowance of dwarf breeders affect reproductive performance of hens and bone development of their progeny

1. An experiment was conducted with 144 caged hens to study the effects of different dietary concentrations of phosphorus and of food restriction on the reproductive performance of dwarf breeder hens and on the growth and the bone development of their progeny. 2. Severe food restrictions at 105 g/hen day compared to 115 g/hen day, decreased hen body weight and hen day egg production. Fertility was unaffected and hatchability slightly depressed by the more severe restriction. 3. Egg and one-day-old chick weights were decreased by limiting the food intake of the breeders but the negative effect disappeared at slaughter (7 weeks). 4. Shell quality decreased as the dietary phosphorus increased and was not affected by food allowance. Albumen quality was slightly impaired in severely restricted hens. 5. Serum inorganic phosphorus in hens and yolk phosphorus increased with increasing dietary phosphorus. Tibial breaking strength and tibial percentage ash of the progeny at hatching was markedly improved in proportion to maternal phosphorus and food intake. This improvement in bone quality was not maintained at 7 weeks. 6. The number of chicks affected by twisted legs (valgus) and dyschondroplasia were similar whatever the maternal diet. The frequency of valgus was higher in males than in females. 7. It is concluded that maternal food intake and phosphorus supply are of importance for the initial bone development of the progeny.

Effects of dietary calcium, available phosphorus and vitamin d on growth rate, food utilisation, plasma and bone constituents and calcium and phosphorus retention of commercial broiler strains

1. The effects of different dietary concentrations of calcium (Ca), available phosphorus (AP) and vitamin D (D) on 5- to 16-day growth performance, and aspects of calcium and phosphorus (P) metabolism of chickens from three commercial strains were studied in two experiments. 2. Increasing dietary Ca reduced weight gain, tibia Ca and P content and increased plasma total Ca, Ca consumption and excretion, whilst dietary Ca at 32 g/kg increased tibia Ca:P ratio, plasma ionized calcium and reduced plasma P, tibia ash, P excretion, excreta moisture and Ca retention. 3. Increasing dietary AP reduced plasma total and ionized Ca and excreta moisture and increased P consumption and excretion, plasma P and tibia ash. 4. The addition of vitamin D increased plasma total and ionized Ca, tibia Ca:P ratio and reduced plasma sodium and P concentrations. 5. Strains differed in their tibia contents of Ca and Ca:P ratios, in response to Ca, AP and vitamin D diets whilst they differed in Ca excretion and excreta moisture caused by feeding either dietary Ca or AP. 6. It was concluded that dietary Ca, AP, vitamin D and strain of broiler chickens influenced the metabolism of Ca and P and that, as a consequence, the tolerance to high dietary Ca. A lean strain of chickens tolerated high dietary calcium better than its fat counterparts.

Effects of Dietary Copper, Cadmium, Iron, Molybdenum and Manganese on Selenium Utilization by the Rat

The possible antagonistic effects of different dietary concentrations of copper (1.3–200 mg/kg), cadmium (1–5 mg/kg), iron (20–500 mg/kg), molybdenum (0.3–50 mg/kg) and manganese (0.2–200 mg/kg) on selenium utilization by the rat were studied by the measurement of the absorption and organ distribution of dietary selenium as [75Se]selenite and by effects on organ glutathione peroxidase (GSH-Px: EC 1.11.1.9) activity. Although a high concentration of copper (200 mg/kg) in the diet did not alter the percentage absorption and total-body retention of doses of 75SeO42- by rats, after such treatment tissue 75Se distribution was changed and was lower total selenium in some tissues. After copper treatment (200 mg/kg diet) GSH-Px activity of liver, testis, kidney and whole blood was also lower. Dietary cadmium, iron, molybdenum and manganese at the concentrations investigated had no significant effects on selenium metabolism. Thus it is unlikely that copper, cadmium, iron, molybdenum and manganese at normal dietary concentrations will have a major effect on selenium metabolism in the rat, especially if adequate amounts of selenium are being consumed.

Influence of different dietary concentrations of linoleic acid on the Essential Fatty Acid (EFA) status and functional characteristics of poricne hepatic and cardiac mitochondria

1. 1. The effect of different dietary concentrations of linoleic acid (0.2, 1.1 and 2.1% of gross energy in experiment 1 and 0.7, 1.6 and 2.3% of gross energy in experiment 2) on the EFA status and the functional characteristics of hepatic and cardiac mitochondria was investigated in pigs raised for 140 days from 10 to 105 kg live wt on their respective diets. 2. 2. As judged from the ratios of 20: 3n9 to 20:4n6 of hepatic and cardiac mitochondrial total lipids the pigs receiving 0.2% of dietary gross energy as linoleic acid were EFA-deficient, while the pigs receiving 0.7% of dietary gross energy as linoleic acid were on the borderline of EFA deficiency. 3. 3. Mitochondrial protein yield and the functional parameters (endogenous respiration, respiration of exogenous NADH, state 2, 3 and 4 respiration, RCI-values, ADP/O ratios and synthetic rates of ATP) as measured in both hepatic and cardiac mitochondria with two substrates pyruvate plus malate and succinate in the presence of rotenone were not significantly ( P > 0.05) affected by the different dietary concentrations of linoleic acid. 4. 4. The findings indicate a slow turnover of EFA and a low desaturation/elongation activity of the associated enzymes in the pig.