Determinants of Farmers’ participation in high value crops in Tanzania

This paper is based on a study undertaken to analyze market participation of tomato smallholder famers in three districts of Morogoro region in eastern Tanzania. A multi-stage random sampling procedure was employed to select the sample. Determinants and extent of market participation were estimated using Heckman selection and outcome equations respectively. It was found that characteristics of market participants and non-market participants were not statistically different. The paper recommends that that the government should beef up extension services especially in the aspect of market information to farmers in order to enlighten them on the recommended production techniques, market price and also to improve tomato production. Moreover, rural information centres as well as mobile telephony system should be formed so as to enhance tomato farmers’ regular access to information on market dynamics.Key words: Market participation, smallholders, high value crops, Tanzania

How to break the impasse between opposing camps in ivory trade debate

First paragraph: Elephants are in an extremely precarious state in both Africa and Asia. Demand for ivory from Africa has caused significant declines in wild populations. This is now accompanied by new demand for elephant skins from Asia. Resuming trade in elephant parts continues to be one proposal for improving conservation outcomes. But the contention that legal trade will curb poaching is not substantiated by available data. In the modern human economic era, there are few examples of wild animals larger than cattle being sustainably harvested.https://theconversation.com/how-to-break-the-impasse-between-opposing-camps-in-ivory-trade-debate-9648

Aspects of Lipid Utilization in the Neonatal Chicken

Lipids play an important role throughout the life of the birds but particularly during embryonic and neonatal periods. Following hatching the lipids are derived from two sources, the residual yolk sac material and the diet. In modern broiler production much emphasis is placed upon the diet, thus providing the chick with a high lipid oriented environment very early in the post-hatch period. This is normally aimed at enhancing rapid growth in birds. However, a combination of exogenous and endogenous lipid sources to the chick during this period is likely to exert enormous pressure on the physiological processes most of which are still in the developmental stage. Thus, the main objectives of the present studies were to investigate the relative roles of the yolk lipids versus dietary lipids during the neonatal period on lipid and fatty acid compositional changes of the residual yolk sac material, liver, gall bladder bile and gastrointestinal tract. In addition the effects of exogenous and endogenous dietary lipids on the establishment of the gastrointestinal tract microflora, lipid and fatty acid digestibilities were studied. During the study the effect of post-hatching age on all the mentioned parameters was also assessed. Three dietary treatments were used. Diet 1 was a complete diet from a commercial company or a diet compounded using a commercially available fat source. This diet contained high levels of unsaturated fatty acids and free fatty acid. Diet 2 was based on tallow oil as the major fat source and thus contained high levels of saturated fatty acids. Diet 3 was based on soyabean oil as the major fat source and contained high levels of unsaturated fatty acids. The diets were formulated in such a way as to provide adequate levels of other nutrients. Standard procedures for chick rearing and feeding were followed. Established analytical methods for lipid and fatty acids were used throughout. Experiment 1 involved a study on the effects of post-hatching age and dietary fat sources on the lipid and fatty acid compositional changes of the residual yolk sac material, liver and gall bladder bile during the first 12 post-hatch days. The results obtained showed that both the weight and lipid compositions of the residual yolk sac material and the liver were significantly affected by post-hatching age. The changes included significant decline in the weight of residual yolk sac material from about 11% of the total weight of the chick immediately post-hatch to less than 0.1 percent of the chick's body weight by day 12 post-hatch. Between day 1 to 9 post-hatch the rate of decline was higher in chicks receiving the commercial diet and the tallow oil based diet, but no further differences were observed after day 9. Significant increases in the proportion of cholesterol esters and decreases in triglyceride and phospholipid fractions with post-hatching age were observed for all dietary treatments. Dietary effects were also noted, for cholesterol ester and triglyceride, proportions being significantly higher and lower, respectively, in chicks receiving the tallow oil based diet. In common with the residual yolk sac material, the proportion of liver tissue to the chick's body weight was significantly affected by age, particularly between days 1 and 3 post-hatch during which a 50 percent increase was observed in all dietary treatments. After day 3 post-hatch increases were observed only in chicks receiving the commercial diet and the soyabean oil based diet, whilst, decreases occurred in chicks receiving the tallow oil based diet. Liver lipid compositional changes with post-hatching age were characterised by significant decreases of cholesterol esters from 77 to less than 2 percent of total lipid present on day 1 and day 12 post-hatch, respectively. Concomitantly there were significant increases in the triglyceride and phospholipid proportions, whilst, minor changes occurred in the other lipid fractions. Dietary effects on cholesterol esters and triglyceride levels were also observed, levels being higher and lower in chicks receiving the soyabean oil based diet. The lipid composition of the gall bladder bile was significantly affected by post-hatching age in particular the increase in triglyceride levels. In all the tissues studied the effect of age and dietary fat source on fatty acid composition was relatively small. In experiment 2, the influences of the post-hatching age and dietary fat source on the lipid and fatty acid compositional changes in relation to lipid digestion and absorption within the different sections of the gastrointestinal tract were studied. The major feature observed throughout the 12 day post-hatch period was the high phospholipid levels (more than 60 percent of total lipid present) within the duodenal contents irrespective of the dietary treatment. At day 3 post-hatch and in all subsequent days high proportions of triglyceride and free fatty acid were observed in GIT sections beyond the duodenum. It was clear from this study that most of the processes of lipid digestion occurred beyond the duodenum. The proportion of free fatty acid remained high along the remaining sections of the gastrointestinal tract in all the dietary treatments, particularly in chicks receiving the tallow oil based diet

Species and gender differentiation between and among domestic and wild animals using mitochondrial and sex-linked DNA markers

In many African countries accurate and reliable identification of poached wildlife products like carcasses or meat presents a big problem when morphological characters such as skin hair or bones are missing. We describe a molecular based approach that has a potential of serving as a forensic tool in game meat identification in Africa. A mitochondial DNA marker (mt700) and one restriction enzyme, Rsa1 were used in the PCR-RFLP species identification of game meat obtained from two National Parks in Tanzania. Species-specific reference DNA fragment patterns were obtained using fresh meat from ten wildlife and four domesticated species. All species except the zebra, produced unique monomorphic RFLP patterns. Collectively, these patterns demonstrate the potential ability of genetic techniques for discriminating between and among wildlife and domestic species. The reference PCR-RFLP fragments enabled species identification of about 79% of unknown meat samples. In addition, sex was alsoassigned to all of the samples following successful amplification of gender-specific, SRY and ZFY/X, chromosomal domains. Although the present study has been conducted on a limited range both in numbers and genetic diversity of wildlife species present in Africa, the results demonstrate thepotential usefulness of the DNA approach in wildlife forensics in the continent

Studies on the Effects of Trypanosoma congolense Infection on the Reproductive Function of the Ram

This thesis describes a series of studies carried out in Scottish blackface rams experimentally infected with Trypanosoma congolense stabilates 57/10 and 57/11 (originally imported from ILRAD, Kenya as ILRAD 1180) with the primary aim of determining the effects of infection on the function of the hypothalamo-pituitary-gonadal axis. The studies also investigated the possibility that pyrexia is responsible for inducing gonadal endocrine and exocrine dysfunctions in infected animals. In addition the effect of infection on the function of the hypothalamo-pituitary-adrenal (HPA) axis was assessed in order to determine whether reproductive dysfunction generally seen during trypanosomiasis is related to stress caused by the infection. Chapter I comprises an introduction and a literature review on trypanosome- induced reproductive dysfunctions with emphasis on pyrexia and changes in the HPA axis. Chapter II describes the two experiments carried out in rams infected with T. congolense and the general materials and methods used in these studies. Chapter III describes the effects of infection on semen characteristics and pathology of various reproductive organs such as the testis, cauda epididymis, prostate and pituitary gland. It was found that T. congolense induced a progressive deterioration of semen quality in terms of an increased percentage of abnormal spermatozoa in the ejaculate. Progressive non-inflammatory degenerative changes were observed in the testis and prostate gland. The cauda epididymis showed varying degrees of decreased sperm reserve. Trypanosome-induced pyrexia led to an elevation of scrotal temperature in infected rams, suggesting that the changes in the gonads could have been due to increased testicular temperature. Indeed, similar changes were observed in the semen and gonads of uninfected rams following artificial elevation of testicular temperature by scrotal insulation. The pituitary gland showed changes associated with increased basophilic degranulation in infected rams. Changes in plasma concentrations of reproductive hormones in the same rams are described in Chapter IV. It was observed that soon after the onset of parasitaemia, which occurred within 1 - 2 weeks of infection, plasma testosterone concentration declined and levels remained low throughout the infection period. This reduction in plasma testosterone concentration was associated with a progressive and marked decline in testosterone pulse amplitude and testosterone secretion after injection of gonadotrophin-releasing hormone (GnRH) was also depressed throughout the infection period. By four weeks after infection, declining plasma testosterone concentration was accompanied by a significant increase in plasma luteinizing hormone (LH) pulse amplitude and increased pituitary responsiveness (LH secretion) to exogenous GnRH. As the infection progressed up to 8 weeks, the plasma LH concentration declined. This could not be associated with some aspects of gonadal steroid feedback as similar LH changes were observed in infected rams which had been castrated. Neither was the decline in plasma LH concentration caused by the inability of the pituitary gland to secrete and release LH as secretion of LH in response to exogenous GnRH was not impaired throughout the infection period. It was therefore concluded that the decline in plasma LH concentration after 8 weeks of infection was possibly induced by a progressive impairment of the ability of the hypothalamus to synthesize and/or release GnRH. Gonadal steroidogenesis in infected rams was investigated in the in vitro experiments described in Chapter V. This work showed that the alteration in plasma testosterone concentradon following infection was associated with a decline in Leydig cell steroidogenesis, possibly mediated by increased testicular temperature affecting testosterone biosynthetic enzymes. However, by 4 weeks after infection, reduced plasma testosterone in infected animals was exacerbated by the impaired ability of the testes to release testosterone into the circulation resulting in a significant increase in intratesticular testosterone content. A similar increase was also observed in scrotal- insulated rams and it was therefore suggested that changes in intratesticular testosterone in infected rams at 4 weeks of infection was associated with a trypanosome-induced increase in testicular temperature perhaps through an effect on testicular blood flow. The effects of T. congolense infection on the function of the HPA axis in rams and the relationship between this and the changes in the hypothalamo-pituitary-gonadal axis are described in Chapter VI

The potential of mitochondrial DNA markers and polymerase chain reaction-restriction fragment length polymorphism for domestic and wild species identification

Poaching is increasingly presenting challenge to conservational authorities in Africa. Accurate and reliable methods for the identification of poached wildlife meat when morphological features aremissing, has been lacking in Africa. We describe a molecular based approach that has a potential of serving as a tool for game and domestic meat identification in Africa. A mitochondrial (mt246) markerand Rsa1 restriction enzyme were used in the PCR-RFLP species identification of game and domestic meat. Species-specific reference DNA fragment patterns were obtained using fresh meat from ten majorwild herbivores, representing the highly targeted wild meat species in Tanzania and four domesticated animal species. With the exception of the zebra, all species produced unique monomorphic RFLPpatterns that were species specific. These reference fragment patterns enabled identification of about 75% of unknown meat samples, demonstrating the ability of the technique in discriminating betweenand among wild and domestic species. The results provide preliminary promising fingerprints which need further validation for future use for the control of the up-surging bush meat trade in the continent

Multiplicity of infections and level of recrudescence in Plasmodium falciparum malaria in Mlimba, Tanzania

Polymorphism and antigenic variation are important biological survival strategies of malaria parasites determining the episode, outcome and implications of treatment interventions. In P. falciparum, polymorphic antigens are associated with the asexual blood-stage; merozoite surface protein 2 (MSP2). The MSP2 genes have been invaluable in post-treatment discrimination of parasite resurgence fromnew infection, especially in high transmission areas. We performed polymerase chain reaction (PCR) on DNA extracted from blood samples of 141 malaria-infected infants, followed by restriction fragmentlength polymorphism (RFLP) of PCR products. The findings showed multiplicity of infections of single to six infections with an average of 2.58 infections per patient. Single infections of either 3D7 or FC27allelic families of the MSP2 gene occurred in 51 patients (50.5%) out of all PCR-RFLP successful samples (n = 101). Out of 15 (10.6%) follow up samples with resurgent parasitaemia, 3 (20%) sampleshad recrudescent infections while 12 (80%) had variable results. Our findings provide an insight on the prevalence of the genetic determinants of suphadoxine-pyrimethamine (SP) resistance in Mlimba during the study period, and in the face of rapidly spreading resistance, calls for the periodic surveillance in order to timely detect early warning signal of the deteriorating SP cure rate

Media, Health Workers, and Policy Makers' Relationship and Their Impact on Antimalarial Policy Adoption: A Population Genetics Perspective

Drug resistance negatively impacts malaria treatments, making treatment policy revision unavoidable. So far, studies relating sociopolitical and technical issues on policy change with malaria parasite genetic change are lacking. We have quantified the effect of malaria treatment policy on drug pressure and the influence of the media, policy makers, and health worker relationship on parasite population genetic change in Kilombro/Ulanga district. Cross-sectional surveys of asymptomatic infections conducted before, during and after the switch from chloroquine to sulphadoxine/pyrimethamine were used for genetic analysis of SP resistance genes in 4,513 asymptomatic infections identified, and their frequency change was compared with retrospective study of the documented process of policy change. Highly significant changes of dhfr and dhps resistance alleles occurred within one year of switch to SP first line, followed by a decline of their rate of selection caused by reduction of SP usage, as a result of negative media reports on SP usage and lack of adequate preparations

Quantification of markers of antimalarial drug resistance from an area of high malaria transmission: Comparing frequency with prevalence

Molecular monitoring of markers of antimalarial drug resistance offers an affordable alternative to the in vivo method for the detection of resistance, and has the potential to guide public health policy in a timely manner. However, the optimal way of analyzing and reporting these data, particularly those emanating from areas of moderate to high malaria transmission, has never been fully explored or agreed upon, given the potential of being confounded by coinfections. By using large number of real field samples, we quantified the difference between prevalence and frequency when reporting field data on antimalarial drug resistance obtained by direct counting of haplotypes. Polymerase chain reaction (PCR) and sequence specific oligonucleotide probing was used to generate point mutations which were used to construct haplotypes. Results indicate that frequency underestimates haplotypes present at low levels while also amplifying haplotypes present at high levels; prevalence on the other hand behaved in a vice versa manner. Both prevalence and frequency are therefore essential, as each may have relevance in different contexts in high malaria transmission settings. Frequency is essential to gauge the impact of intervention on antimalarial drug resistance while prevalence may be more relevant when the aim is to determine parasite clearance. Key words: Molecular markers, polymerase chain reaction (PCR) - sequence specific oligonucleotide probing (SSOP), prevalence, frequency

Participatory involvement of farming communities and public sectors in determining malaria control strategies in Mvomero District, Tanzania

No Abstract