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The chicken major histocompatibility complex B (MHC-B) – a cluster of genes associated with natural disease resistance or susceptibility – has been investigated in experimental and inbred lines by serological typing. However, that method... more
The chicken major histocompatibility complex B (MHC-B) – a cluster of genes associated with natural disease resistance or
susceptibility – has been investigated in experimental and inbred lines by serological typing. However, that method showed some weaknesses for its use on out breeds. This study aims to explore the genetic diversity of the MHC-B of Cameroon indigenous chicken through molecular typing with LEI0258 and MCW0371 microsatellite markers. MHC-B haplotypes of 290 chickens from four agro-ecological zones were identified and compared with published haplotypes. Alleles were analysed for genetic diversity and relationship among Cameroon chicken populations. Hypothetically new LEI0258 alleles and haplotypes were detected. Overall, polymorphism parameters were relatively high in the Cameroon western highlands. The analysis of molecular variance revealed great variability (80.00 percent) between individuals than among and within ecotypes. The inbreeding coefficients of overall populations (FIT), among population (FST) and within population (FIS) were 0.26, 0.04 and 0.22, respectively, and all were highly significant (P < 0.001). A UPGMA tree based on Nei’s DA genetic distances showed a clear distinction between Cameroon and out-groups and a structuring of within-country populations into three clusters. There is a great genetic diversity of the MHC-B in Cameroon native chicken and also a need of sequencing of the identified alleles for an accurate identification prior to their assessment for natural disease resistance and responsiveness to vaccination.
Keywords: Cameroon indigenous chicken, genetic diversity, immunity, major histocompatibility complex B (MHC-B)
susceptibility – has been investigated in experimental and inbred lines by serological typing. However, that method showed some weaknesses for its use on out breeds. This study aims to explore the genetic diversity of the MHC-B of Cameroon indigenous chicken through molecular typing with LEI0258 and MCW0371 microsatellite markers. MHC-B haplotypes of 290 chickens from four agro-ecological zones were identified and compared with published haplotypes. Alleles were analysed for genetic diversity and relationship among Cameroon chicken populations. Hypothetically new LEI0258 alleles and haplotypes were detected. Overall, polymorphism parameters were relatively high in the Cameroon western highlands. The analysis of molecular variance revealed great variability (80.00 percent) between individuals than among and within ecotypes. The inbreeding coefficients of overall populations (FIT), among population (FST) and within population (FIS) were 0.26, 0.04 and 0.22, respectively, and all were highly significant (P < 0.001). A UPGMA tree based on Nei’s DA genetic distances showed a clear distinction between Cameroon and out-groups and a structuring of within-country populations into three clusters. There is a great genetic diversity of the MHC-B in Cameroon native chicken and also a need of sequencing of the identified alleles for an accurate identification prior to their assessment for natural disease resistance and responsiveness to vaccination.
Keywords: Cameroon indigenous chicken, genetic diversity, immunity, major histocompatibility complex B (MHC-B)
Research Interests:
The molecular typing and the indirect ELISA procedure were used to identify some alleles of favorable effect on the antibody response against the Newcastle disease virus (NDV). The NDV seroprevalence was 100.00% with 10.47% suspect and... more
The molecular typing and the indirect ELISA procedure were used to identify some alleles of favorable effect on the antibody response against the Newcastle disease virus (NDV). The NDV seroprevalence was 100.00% with 10.47%
suspect and 89.63% positives. The protective level of ELISA antibody mean titre was 1409.43U/ml and 16.26% of the
tested birds were considered tolerant. A total of 10 alleles of which 4 from the MHC-B Marker LEI0258 and 6 alleles
from 5 QTL markers associated with resistance/tolerance against the NDV, namely LEI0070 (2 alleles) and only 1
allele for ADL0146, LEI0104, ADL0320 and ADL0304 espectively were shown to have a favorable effect on the
antibody titre. The naked neck chicken was associated with high antibody response (1816.27 to 2227.55 U/ml)
compare to the others (1409.48 to 1842.54 U/ml) and their phenotypic frequency was relatively higher (23.08) in the
selected population compare to the sampled population (10.47) but, no MHC or QTL allele were private to the naked
neck. These results suggest an evidence of genetic disease resistance within Cameroon native chicken populations and
confirm the implication of the MHC-B in the immune response in general, and against the Newcastle disease virus in particular.
Keywords: Indigenous chicken; disease resistance; ELISA; molecular typing; Cameroon
suspect and 89.63% positives. The protective level of ELISA antibody mean titre was 1409.43U/ml and 16.26% of the
tested birds were considered tolerant. A total of 10 alleles of which 4 from the MHC-B Marker LEI0258 and 6 alleles
from 5 QTL markers associated with resistance/tolerance against the NDV, namely LEI0070 (2 alleles) and only 1
allele for ADL0146, LEI0104, ADL0320 and ADL0304 espectively were shown to have a favorable effect on the
antibody titre. The naked neck chicken was associated with high antibody response (1816.27 to 2227.55 U/ml)
compare to the others (1409.48 to 1842.54 U/ml) and their phenotypic frequency was relatively higher (23.08) in the
selected population compare to the sampled population (10.47) but, no MHC or QTL allele were private to the naked
neck. These results suggest an evidence of genetic disease resistance within Cameroon native chicken populations and
confirm the implication of the MHC-B in the immune response in general, and against the Newcastle disease virus in particular.
Keywords: Indigenous chicken; disease resistance; ELISA; molecular typing; Cameroon
Research Interests:
Up to 70 percent of farmers in Cameroon raise local chicken for food and income generation, but due to the Newcastle disease the mortality is very high. In his research Mr Blaise Arnaud Hako Touko found that the naked neck gene (Na) has a... more
Up to 70 percent of farmers in Cameroon raise local chicken for food and income generation, but due to the Newcastle disease the mortality is very high. In his research Mr Blaise Arnaud Hako Touko found that the naked neck gene (Na) has a positive effect on the local chickens’ mortality rate, feed conversion ratio and antibody production against the Newcastle disease. The gene also improves acute heat stress tolerance, pluck weight and dressing percentage of local chickens. The findings can be used for genetic improvement strategies for Cameroonian chicken populations, and for better adaptability to poor feed sources, heat stress and
disease resistance. Complementary studies are needed for the identification of potentially important candidate genes.
disease resistance. Complementary studies are needed for the identification of potentially important candidate genes.
Research Interests:
Diseases are a serious threat for family poultry with chickens killed by the Newcastle disease alone, in affected areas. The output is malnutrition, impoverishment of small scale farmers, genetic drift leading to depletion of native... more
Diseases are a serious threat for family poultry with chickens killed by the Newcastle disease alone, in affected areas. The output is malnutrition, impoverishment of small scale farmers, genetic drift leading to depletion of native chicken genetic resources. There are no practical cost effective control strategies. Selection for disease resistance may be a sustainable way to overcome this challenge and the prerequisite is a better knowledge of the MHC complex, a cluster of immune function genes. Molecular typing of the MHC using LEI0258 and MCW0371 microsatellite markers revealed low and high antibody haplotypes as well as 22 New MHC-B alleles of potential interest for disease resistance related breeding strategies.
Research Interests:
The global warming and climatic changes is particularly deleterious to tropical agriculture in general and to the animal genetic resources in particular, impairing initiatives for their sustainable management. In order to contribute to... more
The global warming and climatic changes is particularly deleterious to tropical agriculture in general and to the
animal genetic resources in particular, impairing initiatives for their sustainable management. In order to contribute to
the mitigation of the effects of climate changes on agriculture, this study was carried out to determine the effect of hyperthermia on the haematology and physiological parameters of the local chicken and a commercial broiler breed in tropical environment. For this purpose, pens of local and exotic chicks after the starter phase were conducted
separately at 25 and 35°C. In the two genetic types, the effect of heat stress caused an increase of 525.43% of leukocytes in exotic chickens and of 1778.43% in local chickens. The same was observed for the monocytes in local chickens (227.22%). The mean globular volume, mean cellular haemoglobin and mean cellular concentration in haemoglobin were reduced in the local chicken, by -10.23, -22.87 and -14.07% respectively, but the values of these parameters were increased in exotic chickens by 179.54, 214.09 and 12.36%. The results of heat tolerance indexes suggested that with age the local chicken easily overcome heat stress, while the exotic chicken become increasingly vulnerable. These results have been confirmed by the high mortality rate observed in the commercial stock under heat stress, while there was no mortality among the local chickens.
Key words: Adaptability; blood; chicken; hyperthermia; physiology
animal genetic resources in particular, impairing initiatives for their sustainable management. In order to contribute to
the mitigation of the effects of climate changes on agriculture, this study was carried out to determine the effect of hyperthermia on the haematology and physiological parameters of the local chicken and a commercial broiler breed in tropical environment. For this purpose, pens of local and exotic chicks after the starter phase were conducted
separately at 25 and 35°C. In the two genetic types, the effect of heat stress caused an increase of 525.43% of leukocytes in exotic chickens and of 1778.43% in local chickens. The same was observed for the monocytes in local chickens (227.22%). The mean globular volume, mean cellular haemoglobin and mean cellular concentration in haemoglobin were reduced in the local chicken, by -10.23, -22.87 and -14.07% respectively, but the values of these parameters were increased in exotic chickens by 179.54, 214.09 and 12.36%. The results of heat tolerance indexes suggested that with age the local chicken easily overcome heat stress, while the exotic chicken become increasingly vulnerable. These results have been confirmed by the high mortality rate observed in the commercial stock under heat stress, while there was no mortality among the local chickens.
Key words: Adaptability; blood; chicken; hyperthermia; physiology
Research Interests:
This study was carried out to determine the effect of hyperthermia on growth parameters of the local chicken and exotic broiler breed in tropical environment at 25 and 35°C. The chickens were raised at 25°C consumed more food than those... more
This study was carried out to determine the effect of hyperthermia on growth parameters of the local chicken and
exotic broiler breed in tropical environment at 25 and 35°C. The chickens were raised at 25°C consumed more food than those raised under hyperthermia. The consumption reduction in local chickens under thermal stress varies from -
2.39 to -7.90%. In hyperthermia, water consumption increased in exotic chicken (4.99 to 7.04%) but, decreased
(7.50%) in local chicken. The weight loss at 8th weeks in exotic chickens varies from -24 to -29%, while the local
chicken under the same challenging stress increased live weight by 10 to 34%. Hyperthermia resulted in a reduction
of the weight gain of -3.09% in local chicken and -14.56% in exotic chicken. The consumption index increased by
57.72% and 60.67% respectively in local chicken and exotic strain respectively. The carcass yield decreased by 25.79
and 15.01% respectively in exotic and local birds respectively. In the two genetic types, the induction of heat stress caused a decline in the proportion of the pancreas by 37.83% in the local chicken and by 25% in the exotic strain. The proportions of other organs declined in local chicken (-22.34% to -36.36%) and increased in exotic chickens (10.33 to 24.59%). These results showed that local chicken have better adaptability to heat stress than exotic chicken.
Key words: Adaptability; chicken; hyperthermia; productivity
exotic broiler breed in tropical environment at 25 and 35°C. The chickens were raised at 25°C consumed more food than those raised under hyperthermia. The consumption reduction in local chickens under thermal stress varies from -
2.39 to -7.90%. In hyperthermia, water consumption increased in exotic chicken (4.99 to 7.04%) but, decreased
(7.50%) in local chicken. The weight loss at 8th weeks in exotic chickens varies from -24 to -29%, while the local
chicken under the same challenging stress increased live weight by 10 to 34%. Hyperthermia resulted in a reduction
of the weight gain of -3.09% in local chicken and -14.56% in exotic chicken. The consumption index increased by
57.72% and 60.67% respectively in local chicken and exotic strain respectively. The carcass yield decreased by 25.79
and 15.01% respectively in exotic and local birds respectively. In the two genetic types, the induction of heat stress caused a decline in the proportion of the pancreas by 37.83% in the local chicken and by 25% in the exotic strain. The proportions of other organs declined in local chicken (-22.34% to -36.36%) and increased in exotic chickens (10.33 to 24.59%). These results showed that local chicken have better adaptability to heat stress than exotic chicken.
Key words: Adaptability; chicken; hyperthermia; productivity
Research Interests:
This study had as objective to contribute to the genetic improvement of the local chicken by direct and reciprocal crossings with an exotic standard strain. The experimental birds where the parental genotypes HH (pure Hubbard strain; 88),... more
This study had as objective to contribute to the genetic improvement of the local chicken by direct and reciprocal crossings with an exotic standard strain. The experimental birds where the parental genotypes HH (pure Hubbard strain; 88), LL (pure local chicken; 58) and their reciprocal crossbreds HL (crossbreds Hubbard rooster x local hen; 36) and LH (crossbreds local rooster x Hubbard hen; 39). It came out from the study that the effect of genotype was significant on all the parameters under study. The products of the crossings (F1) presented intermediate performances to those of their pure parents HH and LL.
The effect of the heterosis was in general weak and positive only in some cases. As related to food consumption and feed efficiency, negative heterosis revealed a lower consumption of the crossbreds and a better food conversion for the LH at the seventh week (-15.6% and -19.7%). The mean parents in general had some performances higher to those of their descendants, notably for growth and conformation traits, probably due to breeds used. The results obtained for LH in relation to HL are confirmed by the reciprocal effect analysis. It revealed that for all parameters, in general, notably the live weight (311.6 g), the DWG (19.3 g), the consumption index (-2.5) and the carcass yield (577.8g), the local rooster x exotic hen crossing was superior to the exotic rooster x local hen crossing. This crossing could, consequently, allow higher genetic gains in shorter time and therefore reach the objectives of the crossings more quickly. Crossings with Hubbard breed upgraded the local chicken by 6.8% and 80.6% of live weight respectively in HL and LH genotypes, and carcass percentages by 17.5% and 143.6% in the same genotypes as compared to the pure local parental genotype. The coefficient of variation for live weight at 7th week of age was 13.8% in HL and 16.1%in LH, while the carcass yield varied by 17.3% and 7.4% respectively in HL and LH.
The local fowl could then be favourably used as sire breed in crossbreeding programs, but several crossing generations and selection will be needed for homogenization and stabilization of a LH genotype
Key words: exotic chicken, crossbreds, hybrid vigour, maternal effects, native chicken
The effect of the heterosis was in general weak and positive only in some cases. As related to food consumption and feed efficiency, negative heterosis revealed a lower consumption of the crossbreds and a better food conversion for the LH at the seventh week (-15.6% and -19.7%). The mean parents in general had some performances higher to those of their descendants, notably for growth and conformation traits, probably due to breeds used. The results obtained for LH in relation to HL are confirmed by the reciprocal effect analysis. It revealed that for all parameters, in general, notably the live weight (311.6 g), the DWG (19.3 g), the consumption index (-2.5) and the carcass yield (577.8g), the local rooster x exotic hen crossing was superior to the exotic rooster x local hen crossing. This crossing could, consequently, allow higher genetic gains in shorter time and therefore reach the objectives of the crossings more quickly. Crossings with Hubbard breed upgraded the local chicken by 6.8% and 80.6% of live weight respectively in HL and LH genotypes, and carcass percentages by 17.5% and 143.6% in the same genotypes as compared to the pure local parental genotype. The coefficient of variation for live weight at 7th week of age was 13.8% in HL and 16.1%in LH, while the carcass yield varied by 17.3% and 7.4% respectively in HL and LH.
The local fowl could then be favourably used as sire breed in crossbreeding programs, but several crossing generations and selection will be needed for homogenization and stabilization of a LH genotype
Key words: exotic chicken, crossbreds, hybrid vigour, maternal effects, native chicken
Research Interests:
A study was done at the Teaching and Research Farm of the University of Dschang in order to determine the effects of the genetic group and the sex on the haematological parameters and the viability of the local domestic fowl in Cameroon.... more
A study was done at the Teaching and Research Farm of the University of Dschang in order to determine the effects of the genetic group and the sex on the haematological parameters and the viability of the local domestic fowl in Cameroon. It was carried on 301 birds of 16 weeks old of both sexes belonging to 4 genetic groups; Nakedneck [Na], Feathered shank [Pti], Crested head [Cr] and Normal feathered [na+ pti+ cr+].
The 2 way lay out analysis of variance showed that the packed cell volume (PCV) and the total cell count were significantly influenced (P<0.01) by the genetic group and the sex. Irrespective of the sex, the Crested head was the best (P<0.01) with the highest PCV while the Feathered shank was the least. The PCV was higher (P<0.01) in males compared to females. The erythrocyte count was higher (P<0.01) in Crested head compared to others, while no significant difference were observed as the sex was concerned for this parameter. The leukocyte count was higher (P<0.01) in Feathered shank and Crested head as the genetic group was concerned and in males compared to females. Overall, according to the differential cell count, no significant difference was observed among genetic groups and sexes, except the monocyte percentage which was higher (P<0.01) in Nakedneck and Crested head females compared to males. A slight heterophilia was noted among the 4 genetic groups. The best viability rate (84.23 %) was observed in Normal feathered while the least one (60.63 %) was in Feathered shank.
Our results showed that the Normal feathered is the least vulnerable while the Feathered shank is the most vulnerable of the 4 genetic groups as heterophilia is involved.
Keywords: differential cell count, local breed, pack cell volume, rusticity, total cell count
The 2 way lay out analysis of variance showed that the packed cell volume (PCV) and the total cell count were significantly influenced (P<0.01) by the genetic group and the sex. Irrespective of the sex, the Crested head was the best (P<0.01) with the highest PCV while the Feathered shank was the least. The PCV was higher (P<0.01) in males compared to females. The erythrocyte count was higher (P<0.01) in Crested head compared to others, while no significant difference were observed as the sex was concerned for this parameter. The leukocyte count was higher (P<0.01) in Feathered shank and Crested head as the genetic group was concerned and in males compared to females. Overall, according to the differential cell count, no significant difference was observed among genetic groups and sexes, except the monocyte percentage which was higher (P<0.01) in Nakedneck and Crested head females compared to males. A slight heterophilia was noted among the 4 genetic groups. The best viability rate (84.23 %) was observed in Normal feathered while the least one (60.63 %) was in Feathered shank.
Our results showed that the Normal feathered is the least vulnerable while the Feathered shank is the most vulnerable of the 4 genetic groups as heterophilia is involved.
Keywords: differential cell count, local breed, pack cell volume, rusticity, total cell count
Research Interests:
The effect of genetic types of local domestic fowl on live body weight was done at the Teaching and Research Farm of the University of Dschang. It was carried on 478 chicks of both sexes belonging to 4 genetic types; Naked Neck (Na),... more
The effect of genetic types of local domestic fowl on live body weight was done at the Teaching and Research Farm of the University of Dschang. It was carried on 478 chicks of both sexes belonging to 4 genetic types; Naked Neck (Na), Feathered Shank (Pti), Crested Head (Cr) and Normal Feathered (na+, pti+, cr+).
A 3 way lay out analysis of variance showed that the evolution of the live body weight is significantly influenced (P<0, 01) by genetic type, sex and season. Irrespective of sex and season, the Feathered Shank was the least performant (373 to 717g) from the 9th to the 14th week. The best performances were those of the Naked Neck and the Normal Feathered (385 to 802g and 381 to 798g) which were however comparable at that same period. However, the feathered shank showed lateness in growth and was the most performant at the end of the trial with a live body weight of 920g at 16 week of age. In general, the Crested Head was the least performant (29.9 to 848g) from day old to 16 weeks of age. Sexual dimorphism was greatly in favor of males (P<0.05), with the highest value obtained from feathered shank males (34.1 to 1115 g) during the raining season and the least (29.2 to 724 g) observed on crested head females in the dry season. Irrespective of the genetic type and sex, significantly (P<0.01) heavier live body weight (32.1 to 911 g) were obtained during the rainy season compared to the dry season (30.5 to 866g).
The estimated effects of the genetic type (Gi), sex (Hs) and season (Ht) on live body weight showed that sex and season effects are constant from one type to another and were used to estimate an equation for the prediction of genetic type effect (Gi = Yijk - μ (1+Hs+Ht) - eijk,) from known live body weight (Y) and the estimated constants expressed in % of live body weight.
Keyword: Cameroon, live body weight, local fowl, modeling
A 3 way lay out analysis of variance showed that the evolution of the live body weight is significantly influenced (P<0, 01) by genetic type, sex and season. Irrespective of sex and season, the Feathered Shank was the least performant (373 to 717g) from the 9th to the 14th week. The best performances were those of the Naked Neck and the Normal Feathered (385 to 802g and 381 to 798g) which were however comparable at that same period. However, the feathered shank showed lateness in growth and was the most performant at the end of the trial with a live body weight of 920g at 16 week of age. In general, the Crested Head was the least performant (29.9 to 848g) from day old to 16 weeks of age. Sexual dimorphism was greatly in favor of males (P<0.05), with the highest value obtained from feathered shank males (34.1 to 1115 g) during the raining season and the least (29.2 to 724 g) observed on crested head females in the dry season. Irrespective of the genetic type and sex, significantly (P<0.01) heavier live body weight (32.1 to 911 g) were obtained during the rainy season compared to the dry season (30.5 to 866g).
The estimated effects of the genetic type (Gi), sex (Hs) and season (Ht) on live body weight showed that sex and season effects are constant from one type to another and were used to estimate an equation for the prediction of genetic type effect (Gi = Yijk - μ (1+Hs+Ht) - eijk,) from known live body weight (Y) and the estimated constants expressed in % of live body weight.
Keyword: Cameroon, live body weight, local fowl, modeling