Effects of imperfect albinism (sal-s) on growth in a heavy line of chickens

Original Research: Effect of various dietary fats on fatty acid profile in duck liver: Efficient conversion of short-chain to long-chain omega-3 fatty acids

Omega-3 fatty acids, especially long-chain omega-3 fatty acids, have been associated with potential health benefits for chronic disease prevention. Our previous studies found that dietary omega-3 fatty acids could accumulate in the meat and eggs in a duck model. This study was to reveal the effects of various dietary fats on fatty acid profile and conversion of omega-3 fatty acids in duck liver. Female Shan Partridge Ducks were randomly assigned to five dietary treatments, each consisting of 6 replicates of 30 birds. The experimental diets substituted the basal diet by 2% of flaxseed oil, rapeseed oil, beef tallow, or fish oil, respectively. In addition, a dose response study was further conducted for flaxseed and fish oil diets at 0.5%, 1%, and 2%, respectively. At the end of the five-week treatment, fatty acids were extracted from the liver samples and analyzed by GC-FID. As expected, the total omega-3 fatty acids and the ratio of total omega-3/omega-6 significantly increased in both flaxseed and fish oil groups when compared with the control diet. No significant change of total saturated fatty acids or omega-3 fatty acids was found in both rapeseed and beef tallow groups. The dose response study further indicated that 59-81% of the short-chain omega-3 ALA in flaxseed oil-fed group was efficiently converted to long-chain DHA in the duck liver, whereas 1% of dietary flaxseed oil could produce an equivalent level of DHA as 0.5% of dietary fish oil. The more omega-3 fatty acids, the less omega-6 fatty acids in the duck liver. Taken together, this study showed the fatty acid profiling in the duck liver after various dietary fat consumption, provided insight into a dose response change of omega-3 fatty acids, indicated an efficient conversion of short- to long-chain omega-3 fatty acid, and suggested alternative long-chain omega-3 fatty acid-enriched duck products for human health benefits.

The protective effect of hydrated sodium calcium aluminosilicate against the adverse effects of Aflatoxin B1 on D. melanogaster

The main aim of this study was to investigate the effects of Aflatoxin B1(AFB1) and Aflatoxin B1-hydrated sodium calcium aluminosilicate (HSCAS) on various developmental stages of Drosophila melanogaster. Different concentrations of AFB1and HSCAS-AFB1were administered during the developmental periods of the fly (egg, larvae and pupae). When the F1progeny of control and application groups were compared, AFB1was found to extend the process of metamorphosis and decrease the total number of offspring. However, these negative effects were inhibited with HSCAS treatment at different concentrations (5.0 and 10.0 ppm). These results suggest that HSCAS could effectively inhibit AFB1-induced abnormalities in the developmental stages of D. melanogaster.

Effect of clinoptilolite on performance of Japanese quail (Coturnix coturnix japonica) during experimental aflatoxicosis

Clinoptilolite (CLI, a natural zeolite), incorporated into the diet at 50 g/kg, was evaluated for its ability to reduce the deleterious effects of 2.0 mg total aflatoxin (AF;83.06% AFB1, 12.98% AFB2, 2.84% AFG1 and 1.12% AFG2)/kg diet on growing Japanese quail chicks from 10 to 45 d of age. A total of 40 Japanese quail chicks were divided into 4 treatment groups (control, AF, CLI, AF plus CLI) each consisting of 10 chicks. The performance of the birds was evaluated. The AF treatment significantly decreased food consumption and body weight gain from the 3rd week onwards. The adverse effect of AF on food conversion ratio was also significant from week 4 of the experiment. The addition of CLI to an AF-containing diet significantly reduced the deleterious effects of AF on food consumption, body weight gain and food conversion ratio. Food consumption was reduced by 14% in quail chicks consuming the AF diet without CLI, but by only 6% for quail chicks consuming the AF plus CLI diet. Similarly, overall body weight gain was reduced by 27% in birds consuming the AF diet without CLI, but by only 8% for birds consuming the AF plus CLI diet. The addition of CLI to the AF-free diet significantly decreased food consumption and body weight gain during week 4, but these parameters were similar to the controls in week 5. No mortality was observed in any of the groups. These results suggest that CLI effectively diminished the detrimental effects of AF on the variables investigated in this study.

Effect of sodium bentonite on the performance and blood variables of broiler chickens intoxicated with aflatoxins

1. This study was conducted to evaluate the protective effect of natural sodium bentonite (NaB) in the prevention of toxic effects of aflatoxins. Five hundred and twenty-eight 1-d-old Ross male broiler chickens were housed in pens (22 chickens per pen) for 42 d. There were 3 inclusion rates of NaB (0, 2.5, and 5 g/kg) and 2 of aflatoxins (0 and 3 mg/kg food). Each treatment had 4 replicates of 22 chickens. 2. All chickens treated with aflatoxin and without bentonite were adversely affected. NaB treatment at 5.0 g/kg improved body weights at 42 d of age by 31.3%, increased food intake by 23.8% and improved productive efficiency by 40.1%. Weights of liver, heart, pancreas and crop and biochemical variables were not affected by dietary NaB. However, serum phosphorous concentration was reduced by 30% compared with chickens that received aflatoxin. 3. NaB caused no adverse effects on chickens that did not receive aflatoxin. 4. It is concluded that NaB at pH 7.9 partially neutralises the effects of aflatoxins on broiler chickens when included at 5.0 g/kg in the diet.

Effects of polyvinylpolypyrrolidone, synthetic zeolite and bentonite on serum biochemical and haematological characters of broiler chickens during aflatoxicosis

1. Polyvinylpolypyrrolidone (PVPP), synthetic zeolite (SZ) and bentonite (BNT), when incorporated into the diets at 3, 5 and 5 g/kg respectively, were evaluated for their ability to reduce the deleterious effects of 2.5 mg aflatoxin (AF; 83.06% AFB1, 12.98% AFB2, 2.84% AFG1, and 1.12% AFG2,)/kg diet on growing broiler chickens from 1 day to 3 weeks of age. A total of 210 chicks were divided into 10 treatment groups (control, AF, PVPP, AF plus PVPP, PVPP plus SZ, AF plus PVPP plus SZ, PVPP plus BNT, AF plus PVPP plus BNT, AF plus SZ and AF plus BNT) each consisting of 21 chicks. 2. When compared to control, the AF treatment significantly decreased serum total protein, albumin, inorganic phosphorus, uric acid and total cholesterol, and the values of haematocrit, haemoglobin, mean corpuscular haemoglobin, thrombocyte counts, percentage of lymphocyte and monocyte counts; increased values of white blood cell and heterophil counts. 3. Decreased serum albumin caused by AF was significantly ameliorated by PVPP plus BNT. A similar increase was obtained in serum total cholesterol by adding BNT to the AF-containing diet. 4. The serum uric acid, white blood cell counts and percentage of lymphocyte and monocyte counts were numerically intermediate between control and AF values in all of the adsorbent treatments containing AF. The change in thrombocyte counts was alleviated by all of the adsorbent treatments containing AF, except AF plus SZ. The addition of the adsorbents in the AF-free diets did not significantly alter the serum biochemical and haematological parameters compared to controls.

Utilization of the sex-linked gene for imperfect albinism (S*ALS). 1. Effect of early weight loss on chick metabolism

The sex-linked gene for imperfect albinism (S*ALS) has been associated with slow early growth in some trials but not in others. Albino (59) and nonalbino (73) chicks were raised to 3 d of age to study early growth. At 3 d of age, plasma beta-hydroxybutyrate (beta-HBA) levels were measured and the chicks were euthanatized and dissected to measure liver, gall bladder, and yolk sac weights. Fatty acids of the liver and the yolk sac were also analyzed. On average, albino chicks lost weight between hatch and 3 d of age and nonalbinos gained weight (-2.41 vs 0.74 g/d, P < 0.01). At 3 d of age, livers from albinos contained higher (P < 0.01) levels of docosahexaenoic acid than those of nonalbinos, likely reflecting the dependence on yolk sac nutrients of albinos and on dietary lipids of nonalbinos at this time. Albinos had lower body temperatures (P < 0.01), liver weights (P < 0.01) and gall bladder weights (P < 0.05), and heavier yolk sacs (P < 0.01) than did nonalbinos. Plasma levels of beta-HBA were higher (P < 0.01) for albinos than for nonalbinos. At similar body weights, chicks of both genotypes had similar body temperatures, gall bladder weights, and plasma beta-HBA levels. Linear regressions indicated that in albinos weight loss is associated with larger yolk sacs, smaller livers, larger gall bladders, lower body temperatures, and higher levels of beta-HBA. Yolk sac utilization seemed to be correlated with activation of the digestive system. The inability of starving chicks to use the yolk sac nutrients while lipolysis is taking place suggests that yolk sac absorption does not respond to lipolytic hormones. Because under certain conditions a large proportion of albinos (90% in this experiment) show the symptoms of the starve-out syndrome, the S*ALS gene could serve as a model for the study of this syndrome.

A method for separating sex-linked imperfect albino (S*ALS) and nonalbino embryos before hatch

The feasibility of using the sex-linked gene for imperfect albinism (S*ALS) to sex chicks during incubation by candling was studied. With this technique, the dark eye of nonalbino embryos can be positively identified. Two trials were performed. In a first trial, 66.5 and 89.5% of the 254 nonalbino and 210 albino chicks produced in four hatches were correctly identified by candling at 7 d of incubation. Of 191 eggs predicted to be nonalbinos, 22 were albinos, resulting in an overall accuracy of 88.5% for identification of nonalbino embryos. In a second trial, the accuracy of the technique from 7 to 10 d of incubation was evaluated. Increased age resulted in a tendency for lower accuracy, but candling at 8, 9, or 10 d of incubation allowed identification of a greater (P < 0.05) proportion of the nonalbino population than at 7 d of incubation. Candling at 8 d of incubation allowed identification of nonalbinos and albinos with an accuracy of 81.3 and 84.9%, respectively, suggesting that the ALS gene could be used to sex chicks during incubation when used in a sex-linked cross. This technique may prove advantageous to the laying industry because of savings of incubator and hatcher space. The males of commercial layer lines are normally killed at hatch. Reducing the number that hatch by eliminating them before 10 d of incubation could diminish animal welfare concerns.

Production and quality of eggs from sex-linked imperfect albino (sal-s) and nonalbino (s+) hens kept under commercial conditions

The beneficial effects of the gene for imperfect albinism on egg production were investigated under commercial conditions. In one line (Line 8) but not in another (Line 3), hen-day egg production of albinos from 46 to 75 wk of age was higher than that of nonalbinos (76.1 vs 72.6%) resulting in higher overall hen-day (71.1 vs 69.3%, P < .08) and hen-housed (276.3 vs 263.6 eggs) egg production by albino hens. Egg production of Line 8 albinos was not different than that of one of two commercial strains (Strain A) included as a control (76.1 vs 75.6%, P > .05). In data from Lines 3 and 8 combined, sexual maturity of albinos was delayed by 3.0 d. Mortality was higher for albinos than nonalbinos (3.6 vs 1.8%) during the first 2 wk of brooding and lower for albinos (5.8 vs 8.9%) during the laying period. Eggs from albinos weighed less (53.8 vs 55.3 g), had smaller yolks (16.9 vs 17.6 g) and shells (5.16 vs 5.27 g), and firmer albumen (5.9 vs 5.6 mm). The results suggest that the gene produces beneficial effects on egg production under commercial conditions.

Biotechnological applications of research on animal pigmentation

The implications of primary research on pigmentation for the colour manipulation of animal species of economic importance, and the facilitation of specific processes in biotechnology are discussed. Pigment technologists, especially poultry and fish nutritionists, are concerned with achieving the often specific type and degree of coloration demanded by consumers of various products (notably egg yolk, eggshell, broiler skin and salmon flesh). In most instances involving melanin (pelage, plumage and integument) and porphyrin (eggshell) pigments, the desired coloration is achieved through the use of alternate alleles at gene loci controlling the characters of interest. In contrast, coloration involving carotenoids is controlled primarily through pigment supplementation in the diet. The difference between carotenoids and other pigments involves the strict dietary origin of the former. Factors other than pigment availability, such as body condition, hormonal status and genetic constitution, also affect coloration. Although day-old chicks can be sexed by visual inspection of their genitalia, matings resulting in sex-associated phenotypes are in wide use. The genetic markers involved affect the colour of the plumage. The cloning of genes involved in pigmentation offers the prospect of deciphering the genetic control of animal pigmentation and modifying it to meet specific pigmentation needs.

Research note: the S(al)-c mutation in the chicken is not linked to Rous-associated virus-2 related DNA sequences

A male chicken heterozygous for a gene for sex-linked imperfect albinism (s(al)-c) was used to produce offspring in five dam families. The DNA from 23 offspring (22 females and 1 male) was cut with the restriction enzyme Sac1 and hybridized with a Rous-Associated Virus-2 probe to test for linkage between the gene and endogenous viral (ev) genes. In a second experiment, 15 albino and 15 nonalbino females resulting from 4 males mated to 11 females were studied with the enzymes Sac1 and BamHI. In the first experiment, 10 different ev genes were seen. These, plus seven additional bands were seen in the second experiment. The gene s(al)-c segregated independently of all ev genes, suggesting that it could be used for autosexing of chickens or in layer flocks without causing inherent problems previously associated with K, the gene for slow feathering, caused by essentially complete concordance between K and ev21.

Differential environmental effects on lesions, early growth, and mortality of imperfect albino (Sal-c) chicks

A series of experiments investigated early pleiotropic effects of a gene for imperfect albinism (s(al-c) in a population of chickens at Jouy-en-Josas, France. An elevated incidence of lesions of the navel, hocks, and nares typical of imperfect albinos were seen on these chicks, confirming their existence in this population. Variations in hatching environment and the amount of light in the hatcher both implicated in contributing to the occurrence of lesions of the hocks and nares, but not to those of the naval. In two experiments, using batteries and cages, early growth was reduced among albinos and early mortality was increased. Significant genotype by environment interactions for weight at 4 days and growth to this time, but not thereafter, suggested that the effect is restricted to this time. Unfavorable environments were most deleterious to albinos. In a third experiment, conducted in floor pens, the gene had no effect on either early growth or mortality. There was no effect of the gene on the lesions, early growth, or mortality when carried by heterozygous males (s+/s(al-c)).

Phenotypic, embryonic, and neonatal effects of a gene for sex-linked imperfect albinism (Sal-s) in chickens

Gross phenotypic observations, histology, and tissue culture showed that the gene for sex-linked imperfect albinism that occurred at the University of Saskatchewan (Sal-s), allows a small amount of melanin pigment to be deposited in eyes and feathers. Melanin pigment accumulates in retinal pigment epithelial and cultured neural crest cells, but neural crest cells pigmenting the feathers transfer their pigment as it is produced, and this is seen as a constant amount of color in successive generations of feathers. Despite differences from early reports, it would appear that the phenotype produced by Sal-s is essentially the same as that produced by other Sal mutations. Albinos have a high incidence of lesions in the regions of the navel, the hocks, and the nares, similar to those associated with other hypomelanic mutations in the chicken. Yolk contents appear to be used more slowly by albinos late in incubation. The increased size of the yolk sacs probably contributes directly to producing the navel lesions and indirectly to variation in hatch weight. Albinos have small bursae of Fabricius, reduced hatchability, and early growth.

Effects of imperfect albinism (sal-s) on egg production in two lines of chickens

Two trials were conducted with two different lines of chickens to determine whether a gene for sex-linked imperfect albinism (sal-s) affected various egg production traits. In a line with relatively good egg production, sexual maturity was delayed for albino compared with nonalbino hens, but overall egg production by albinos was higher. The increased production resulted in eggs with reduced yolk and shell weights. Albumen weights were not affected, and because the eggs from albinos were smaller, Haugh unit scores were higher. In another trial, sexual maturity of hens of a heavy line was not affected by the genotype, but these hens did not receive controlled lighting during the growing period. Egg production curves of these hens were very similar to those seen in the first trial. The laying house mortality rates were not affected by the sal-s gene, despite several periods of high environmental temperature. These trials suggest that sal-s could be used in a sex-linked cross of commercial layers or broiler breeders.