Spelling suggestions: "subject:"nitrogenfixing"" "subject:"nitrogenixing""
121 |
Diversidade de rizóbios em Florestas de Araucária no Estado de São Paulo / Rhizobia diversity in Araucaria Forests in São Paulo State, BrazilDaniel Renato Lammel 19 June 2007 (has links)
Araucaria angustifolia (B.) Ktz é de grande importância sócio-ambiental e econômica, sendo que ecossistemas que abrigam esta espécie foram muito degradados pela atividade antrópica, colocando-a em risco de extinção. O ciclo do nitrogênio é de vital importância para a vida, tendo especial importância no desenvolvimento e manutenção de florestas. A entrada de nitrogênio nestes sistemas é dependente de organismos diazotróficos, em especial dos rizóbios, bactérias do solo que podem formar simbiose com leguminosas e fixar nitrogênio atmosférico. O estudo da diversidade de rizóbios pode favorecer o manejo mais adequado de florestas e muitas técnicas são usadas com este fim, nas quais se destacam o uso de plantas iscas, coleta de nódulos de leguminosas a campo, isolamento das bactérias em meios de cultivo, avaliação fenotípica dos isolados e o seqüenciamento do gene 16S rRNA, todas utilizadas neste trabalho. A partir do levantamento de leguminosas no Parque Estadual de Campos do Jordão foram coletadas onze espécies de leguminosas, nove apresentaram nódulos, sendo cinco espécies descritas como nodulantes pela primeira vez. Foram isoladas 212 estirpes de bactérias, havendo variação no formato de nódulos e alta riqueza fenotípica das cepas. Houve variabilidade na diversidade fenotípica de bactérias para cada planta, Galactia crassifolia apresentou o maior valor, enquanto que Mimosa dolens apresentou o menor. Dos 212 isolados, 55 cepas foram capazes de nodular o feijoeiro e 56 de nodular a bracatinga. Foi seqüenciado parcialmente o gene 16S rRNA de 196 estirpes que foram classificadas em oito grupos genotípicos, Pantoea sp. (2%), Pseudomonas sp. (2%), Bradyrhizobium sp1 (10%), Bradyrhizobium sp2 (7%), Rhizobium sp. (1%), Burkholderia sp1 (14%), Burkholderia sp2 (26%) e Burkholderia sp3 (38%). A análise filogenética mostrou que a maioria dos grupos pertence a gêneros taxonomicamente relacionados a rizóbios. Houve variação na diversidade genotípica das bactérias em relação às plantas das quais foram isoladas, G. crassifolia apresentou o maior valor, sendo considerada a mais promíscua, enquanto que Acacia dealbata e M. dolens apresentaram os menores valores, sendo consideradas as mais especificas. Mostrou-se que o uso de avaliação fenotípica de rizóbios pode ser inadequado, já que os resultados fenotípicos foram muitas vezes divergentes dos genotípicos. Foram comparadas Florestas de Araucária com diferentes níveis de interferência antrópica (Floresta Preservada, Floresta Plantada e Floresta em Regeneração), usando as plantas-iscas caupi, amendoim, soja, bracatinga, maricá e angico. Maricá foi o mais eficiente na captura de rizóbios, enquanto que bracatinga e caupi apresentaram menor eficiência e as demais plantas falharam. Foram isoladas 78 cepas, sendo classificados como pertencentes a seis grupos genotípicos, Pseudomonas sp. (3%), Xanthomonas sp. (1%), Ralstonia sp. (6%), Herbaspirillum sp. (4%), Burkholderia sp1 (29%) e Burkholderia sp3 (57%), sendo três grupos iguais aos caracterizados anteriormente. A maioria destes grupos está relacionada a rizóbios ou bactérias endofíticas conhecidas. A Floresta em Regeneração apresentou maior diversidade de bactérias isoladas, enquanto que as Florestas Plantada e Preservada apresentaram índices semelhantes. β-rizóbios foram predominantes nas Florestas de Araucária estudadas. / Araucaria angustifolia (B.) Ktz has a great social, environmental and economic importance to south and southeastern Brazil, although ecosystems supporting this species have been degraded by human activity, making it an endangered species. The nitrogen cycle has vital importance for life and has a special role in the development and upkeep of forests. The nitrogen input in these systems is dependent on diazotrophic organisms, especially rhizobia, soil bacteria that may nodulate legumes and fix nitrogen in symbiosis with them. The study of rhizobia diversity may support better forest management practices and many techniques are used in these studies, especially the use of trap-plants, field legume nodule collection, bacteria isolation in culture media, phenotypic analysis of the strains and 16S rRNA gene sequencing, all of which were used in this work. From a survey in Campos do Jordão State Park, nine of eleven legume species collected presented nodules, of which five were reported as nodulating for the first time. A total of 212 bacterial strains were isolated from the nodules. There was great variation of nodule shape and great phenotypic richness among isolates. There was variability in the phenotypical diversity of bacteria in each plant, where Galactia crassifolia showed the highest value, while Mimosa dolens showed the lowest one. Of the 212 strains, 55 were able to nodulate common bean and 56 nodulated bracatinga (M. scabrella). The 16S rRNA gene of 196 strains were partially sequenced and classified into eight genotypic groups: Pantoea sp. (2%), Pseudomonas sp. (2%), Bradyrhizobium sp1 (10%), Bradyrhizobium sp2 (7%), Rhizobium sp. (1%), Burkholderia sp1 (14%), Burkholderia sp2 (26%) and Burkholderia sp3 (38%). Phylogenetic analysis showed that most of the groups belong to bacteria genera related to rhizobia. There was variability in the bacterial diversity related to the isolated plants, where G. crassifolia showed the highest value, being considered the most promiscuous, while Acacia dealbata and M. dolens presented the lowest values, and were considered the most specific ones. The phenotypic analysis of rhizobia was shown to be inappropriate for taxonomy, since the phenotypic results were different from the genotypic ones. Araucaria Forests with different levels of human interference (Preserved Forest, Planted Forest and Recovering Forest) were compared using cowpea, peanut, soybean, bracatinga, maricá (M. bimucronata) and angico (Parapiptadenia rigida) as trap-plants. Maricá was the most efficient in rhizobia capture, while bracatinga and cowpea showed less efficiency and the others failed. A total of 78 strains were isolated and classified into six genotypic groups: Pseudomonas sp. (3%), Xanthomonas sp. (1%), Ralstonia sp. (6%), Herbaspirillum sp. (4%), Burkholderia sp1 (29%) and Burkholderia sp3 (57%), of which three are the same as previously classified. Most of these groups are related to known rhizobia or other endophytic bacteria. The Recovering Forest showed the highest diversity of isolated bacteria, while Planted Forests and Preserved Forest showed similar indeces. β-rhizobia were predominant in the studied areas.
|
122 |
Azotofiksirajuće cijanobakterije u zemljištima Vojvodine i njihova ultrastrukturna i genetička karakterizacija / NITROGEN-FIXING CYANOBACTERIA IN SOILS OF VOJVODINA PROVINCE AND THEIR ULTRASTRUCTURAL AND GENETIC CHARACTERIZATIONFojkar Oliver 29 September 2016 (has links)
<p>U radu je ispitana zastupljenost azotofiksirajućih cijanobakterija, ukupnog broja algi i ukupnog broja bakterija u različitim tipovima zemljišta na jedanaest lokaliteta u Vojvodini, od čega se sedam nalaze u zaštićenim prirodnim dobrima. Ispitana je brojnost u zavisnosti od dubine pedološkog profila, kao i od godišnjeg doba. Izvršena je izolacija sojeva azotofiksirajućih cijanobakterija, određena njihova taksonomska pripadnost i osnovne citološke karakteristike. Ispitana je ultrastruktura vegetativnih ćelija, heterocista i spoljnih struktura na ćelijama fimbrije i pili, transmisionim elektronskim mikroskopom. Izvršena je genetička karakterizacija izolovanih sojeva azotofiksirajućih cijanobakterija PCR metodom analizom STRR fragmenata DNA.<br />Brojnost azotofiksirajućih cijanobakterija i ukupna brojnost algi je bila znatno veća kod hidromorfnih i halomorfnih zemljišta, nego kod automorfnih zemljišta. Najveća prosečna godišnja brojnost azotofiksirajućih cijanobakterija, u površinskom sloju 0-5cm, je utvrđena kod zemljišta fluvisol u SRP “Koviljsko petrovaradinskom ritu”, 150864 jedinki po gramu apsolutno suvog zemljišta. Zemljište sa najnižom brojnošću azotofiksirajućih cijanobakterija, je gajnjača u NP Fruška gora, 1582 jed./gr zemljišta u površinskom sloju.<br />Kod svih ispitivanih zemljišta brojnost azotofiksirajućih cijanobakterija je bila najveća u površinskom sloju zemljišta, 0-5 cm dubine, opadala je sa dubinom zemljišta i bila najmanja u najdubljem sloju, 30 - 60 cm. Kod najvećeg broja ispitivanih zemljišta brojnost azotofiksirajućih cijanobakterija je bila najveća tokom zimskog perioda. Azotofiksirajuće cijanobakterije su dominantne u našim zemljištima i zastupljene sa 56.27% u odnosu na druge grupe algi.Izolovano je 30 sojeva azotofiksirajućih cijanobakterija: 19 sojeva Nostoc-a, 4 soja Anabaena, 4 Cylindrospermum, i po jedan soj Calothrix, Tolypothrix i Phormidium. Prosečna zastupljenost heterocista, ćelija koje vrše azotofiksaciju, kod roda Nostoc je iznosila 8.28%, Anabaena 4.25%, Cylindrospermum-a 2.93%, Calotrix elenkinii 6.19% i Tolypothrix 7.76%.</p><p>Ultrastrukturnim ispitivanjem, TEM mikroskopom, vegetativnih ćelija azotofiksirajućih cijanobakterija uočili smo inkluzije redovnog pojavljivanja: karboksizome (Cs), cijanoficinkse granule (CG), polifosfatne granule (PG), ribozome (R), lipidne granule (ß –granule) i tilakoide (T), kao i inkluzije neredovnog pojavljivanja: membranom ograničene kristalne inkluzije.<br />Koristeći TEM i tehniku bojenja ćelija sa RR i ultratankih preseka utvrdili smo prisustvo omotača od fimbrija kod tri soja (A.314, A.azollae i N.302) i tipične fimbrije kod dva soja (N.311 i N.9229). Metodom negativnog bojenja NS PTA uočili smo takođe tipične fimbrije, igličastog-dlakastog izgleda, jasnih granica niti kod tri soja (N.302, N.7901 i N.9229), međutim uočili smo i atipične sluzne fimbrije, koje nemaju jasno izražene granice, ali su veoma moćno raširene oko vegetativnih ćelija, kod tri soja (A.314, A.azollae, N.311).<br />Kod simbiotskih-infektivnih sojeva N.7901 i N.9229 javljaju se samo tipične fimbrije iz prve klase, a kod diazotofnih sojeva i simbiotskog - neinfektivnog soja A.azollae javljaju se atipične-sluzne fimbrije iz druge klase.<br />Za ispitivanje sličnosti cijanobakterija metodom PCR-a pomoću STRR konzervativnih sekvenci DNA genoma korišćeno je 39 sojeva azotofiksirajućih cijanobakterija i kod 38 je utvrđeno njihovo prisustvo. Svi sojevi se mogu podeliti u tri grupe, klastera. Prvi klaster je najveći i obuhvata 24 soja i deli se na dva podklastera: Ia koji obuhvata 12 sojeva gde dominiraju sojevi Nostoc-a (8), i podklaster Ib koji obuhvata takođe 12 sojeva, od čega 6 sojeva pripada rodu Anabaena. Podklaster Ia i podklaster Ib pokazuju različitost od 90%. Sva tri simbiozna, infektivna, soja Nostoc-a se nalaze u klasteru I: N.7901, N.9229 i N. 8001. Svaki simbiozni soj Nostoc-a ima genetske sličnosti sa po jednim diazotrofnim sojem Nostoc-a izolovanim iz zemljišta Vojvodine.<br />Klaster II obuhvata sedam (7) sojeva među kojima dominiraju sojevi Cylindrospermum-a, dok klaster III obuhvata 7 sojeva od čega 6 pripadaju rodu Nostoc, a jedan rodu Rivularia.Detaljno poznavanje svojstava izolovanih azotofiksirajućih cijanobakterija doprineće njihovoj budućoj primeni kako u proizvodnji ratarskih i povrtarskih kultura, tako i u biotehnološkoj proizvodnji</p> / <p>In this study examined is the frequency of nitrogen-fixing cyanobacteria, total number of algae and total number of bacteria in different soil types on eleven localities in the Vojvodina Province. Seven out of those eleven localities are found in protected nature reserves. Actually, studied was the number of the cyanobacteria and algae depending on the depth of pedological characterization as well as on season. First, isolated were the types of nitrogen-fixing cyanobacteria, determined was their taxonomic origin and basic cytological characteristics. Also examined was the ultrastructure of vegetative cells, heterocysts and other outer structures on fimbriae and pili cells using TEM, transmission electron microscope. Finally, performed was the genetic characterization of isolated types of nitrogen-fixing cyanobacteria using the PCR method and analyzing STRR fragments of DNA.<br />The presence of nitrogen-fixing cyanobacteria and total number of algae was significantly higher with hydromorphic and halomorphic soils than with authomorphic ones. Highest annual average number of nitrogen-fixing cyanobacteria in the topsoil (0-5 cm) was reported with fluvisol soil in Special Nature Reserve „Koviljsko petrovaradinski rit” (Swamp) and there were 150864 units of bacteria per gram of absolutely dry soil. The soil with the lowest presence of nitrogen-fixing cyanobacteria recorded was cambisol in National Park “Fruska gora” with 1582 units per gram of soil in the topsoil.<br />With all the researched types of soils the number of nitrogen-fixing cyanobacteria was in the topsoil, 0-5 cm of depth and decreased in line with the depth<br />of soil and lowest was at the deepest layer, 30-60cm. The highest frequency of nitrogen-fixing cyanobacteria was found during the winter season with most of the examined soils. Nitrogen-fixing cyanobacteria are the dominant type of bacteria in our soils and are presented with 56, 27% compared to other types of algae.<br />30 strains of nitrogen-fixing cyanobacteria were isolated: 19 types of Nostoc sp., 4 of Anabaena sp. and one in each genus of Calothrix, Tolypothrix and Phormidium.<br />Using ultrastructural examination and TEM microscope when studying vegetative cells of nitrogen-fixing cyanobacteria observed were the inclusions of regular frequency: carboxysomes (Cs), cyanophycin granules (CG) , polyphosphate granules (PG), ribosomes (R), lipid granules (SS -granule ) and thylakoids ( T ) as well as the inclusion of irregular occurrence: a membrane-bound crystal inclusions.<br />Using TEM technique and staining the cells with the RR and ultra thin cross section, we determined the presence of depletion of the fimbriae with three strains (A.314, A.azollae and N.302) and typical fimbriae with the two strains (N.311 and N.9229). Applying the method of negative staining NS PTA also noticed were a typical fimbriae, needle-hairy like looks with clear boundaries with the three strains (N.302, N.7901, N.9229). However, also observed were atypical mucous fimbriae, which do not have clearly expressed borders, but they are very strongly spread around the vegetative cells, with the three strains (A.314, A.azollae, N.311).<br />With symbiotic - infective strains N.7901 and N.9229 only typical fimbriae of first class occurred, and in diazotroph strains and symbiotic – non infectious strain A. azollae found were atypical mucous fimbriae of second class.<br />To test the similarity of cyanobacteria by PCR method and using a STRR - conservative DNA sequence of the genome used were 39 strains fixing cyanobacteria and with 38 established was their presence. All strains can be divided into three groups of clusters. The first cluster is the largest and covers 24 strains, and is divided into two subclusters: Ia which includes 12 strains,where predominant are Nostoc strains ( 8 ) , and subcluster Ib , which also implies 12 strains , out of which 6 strains belong to the genus Anabaena. Subcluster Ia and Ib show a difference of 90 %. All three symbiotic , infectious Nostoc strains are classified in a cluster I: N.7901, N.9229 and N. 8001. Each symbiotic Nostoc strain has a genetic similarity with one di-nitrogen Nostoc strain isolated from a lot of different soils in Vojvodina.<br />Cluster II includes seven (7) strains , including strains among which the predominant are Cylindrospermum ones , while cluster III includes 7 strains of which 6 belong to the genus Nostoc and one to genus Rivularia.<br />Detailed knowledge of the properties of isolated fixing cyanobacteria could contribute to their future application both in the production of field crops and vegetables, as well as in biotechnological production.</p>
|
123 |
The roles of the NOOT-BOP-COCH-LIKE genes in the symbiotic organ identity and in plant development / Les rôles des gènes NOOT-BOP-COCH-LIKE dans l’identité de l’organe symbiotique et le développement des plantes.Magne, Kévin 11 December 2017 (has links)
L’association symbiotique entre les légumineuses et les rhizobia aboutit à la formation de la nodosité fixatrice d’azote. Cet organe symbiotique généré de-novo permet l’hébergement intracellulaire des rhizobia qui, grâce à leurs activités nitrogénase,réduisent l’azote atmosphérique en ammonium, une forme de l’azote directement assimilable par la plante hôte.Les mécanismes moléculaires sous-jacents à la reconnaissance entre les deux partenaires symbiotiques, au processus d’infection et à l’organogénèse de la nodosité sont bien décrits, cependantl’établissement et la maintenance de l’identité de cet unique organe souterrain restent incompris.Les gènes NODULE-ROOT de Medicago truncatula, BLADEON-PETIOLE d’Arabidopsis thaliana et COCHLEATA de Pisumsativum sont membres du clade spécifique très conservé NOOTBOP-COCH-LIKE1 (NBCL1) qui fait partie de la famille des gènesNON-EXPRESSOR OF PATHOGENESIS RELATED PROTEIN1-LIKE. Chez les légumineuses, les membres de ce clade NBCL1 sont connus comme étant des régulateurs clés de l’identité de l’organe symbiotique.Mon travail de thèse a eu pour but d’améliorer la compréhension des rôles des gènes NBCL1, à la fois chez des espèces formant des nodosités indéterminées et déterminées, ainsi que de découvrir de nouveaux acteurs moléculaires impliqués dans l’identité de la nodosité dont la régulation est dépendante des gènesNBCL1, essentiellement par l’utilisation de mutants TILLING, Tnt1et LORE1 originaux chez trois espèces de légumineuses: la luzerne tronquée, le petit pois et le lotier.Ce travail rapporte essentiellement l’identification et la caractérisation de nouveaux mutants affectés dans des gènes qui font partie d’un second sous-clade NBCL2 spécifique des légumineuses.Nous avons révélé que les membres de ce sous-clade spécifique des légumineuses NBCL2 jouent d’importants rôles dans le développement de la nodosité, dans l’établissement et la maintenance de l’identité de la nodosité et par conséquence dans le succès et l’efficacité de l’association symbiotique.Ce travail suggère aussi qu’au cours de l’évolution, le programme de développement de la nodosité a recruté des mécanismes de régulations préexistants afin de réguler le développement de la nodosité et son identité, tel que le module de régulation impliquant des interactions entre des protéines NBCL et des facteurs de transcriptions basic leucine zipper de type TGACG. Nous avons identifié le facteur de transcription MtPERIANTHIA-LIKE, comme un premier partenaire protéique interagissant avec des protéines NBLC dans un contexte de nodosité symbiotique. Les gènes NBCL sont aussi impliqués dans les réseaux de régulations qui contrôlent le développement et le déterminisme de nombreux organes végétatifs et reproductifs aériens et sont également impliqués dans la capacité d’abscission de ces organes.Finalement, ce travail thèse a eu pour objectif d’explorer les rôles de ces gènes NBCL très conservés, dans le développement de la graminée non-domestiquée, Brachypodium distachyon. / The symbiotic interaction between legumes andrhizobia results in the formation of a symbiotic nitrogen fixingnodule.This de-novo generated symbiotic organ allows the intracellularaccommodation of the rhizobia which reduces through theirnitrogenase activity the atmospheric nitrogen in ammonium, anitrogen form usable by the host plant.The molecular mechanisms underlying the symbiotic partnersrecognition, the infection process and the nodule organogenesis arewell described, however the identity establishment and maintenanceof this unique underground organ remain mis-understood.The Medicago truncatula NODULE-ROOT, the Arabidopsisthaliana BLADE-ON-PETIOLE and the Pisum sativumCOCHLEATA genes are members of a highly conserved NOOTBOP-COCH-LIKE1 (NBCL1) specific clade that belongs to theNON-EXPRESSOR OF PATHOGENESIS RELATED PROTEIN1-LIKE gene family. In legumes, the members of this NBCL1 cladeare known as key regulators of the symbiotic nodule identity.The present thesis work aims to better understand the roles of theNBCL1 genes, in both indeterminate and determinate nodule formingspecies and to discover new molecular actors involved in theNBCL1-dependent regulation of the nodule identity essentially usingnovel TILLING, Tnt1 and LORE1 insertional mutants in three legumespecies, Medicago, Pisum and Lotus.This thesis work has allowed the identification and thecharacterization of new mutants for genes belonging to a secondarylegume-specific NBCL2 sub-clade. We revealed that the members ofthis legume-specific NBCL2 sub-clade play important roles in noduledevelopment, identity establishment and maintenance, andconsequently in the success and in the efficiency of the symbioticassociation.This thesis work also shows that during evolution, the noduledevelopmental program has recruited pre-existing regulatorymechanisms for the nodule development and identity, such as theregulatory module involving interactions between NBCL proteins andTGACG type basic leucine zipper transcription factors. We identifiedthe transcription factor, MtPERIANTHIA-LIKE, as a first interactingpartner of NBCL proteins in a context of root nodule symbiosis.NBCL genes are also involved in the regulatory networks thatcontrol the development and the determinacy of many abovegroundvegetative and reproductive organs and were also shown as involvedin their abscission ability.In this thesis we also explored the roles of these highly conservedNBCL genes in the development of the non-domesticated grass,Brachypodium distachyon.
|
124 |
Use of plant growth promoting endophytic bacteria to alleviate the effects of individual and combined abiotic stresses on plants as an innovative approach to discover new delivery strategies for bacterial bio-stimulantsTufail, Muhammad Aammar 19 May 2021 (has links)
Bacterial endophytes are the organisms that live inside the plant for a full or a part of their life cycle. Endophytic bacteria have captured the interest of agriculture industry due to their plant beneficial properties, such as synthesis of phytohormones, solubilization of soil nutrients, and alleviation of biotic and abiotic stresses. Several studies have reported that stress tolerant endophytic bacteria can work with a similar performance as non-stressed conditions when inoculated to the plants under stressed conditions. Combination of abiotic stresses such as salinity, drought and low nitrogen stress can have additive or agonistic effects on bacterial and plant growth, and their interactions. However, very few studies have reported the impact of combined stress on endophytic bacterial assisted plant growth promotion. Therefore, understanding the underlying mechanisms of endophytic bacterial assisted plant’s tolerance abiotic stresses may provide the means of better exploiting the beneficial abilities of endophytic bacteria in agricultural production. Thus, the aim of this thesis was to study the stress tolerance mechanisms, beneficial characteristics, and plant growth promotion characteristics of endophytic bacteria under individual and combined abiotic stresses. Transcriptome analysis of endophytic bacteria revealed that tolerance mechanisms to deal with one kind of stress is different than concurrent stresses. Salinity and drought stress largely modulated the genes involved in flagellar assembly and membrane transport, showing reduced motility under stress conditions to preserve the energy. Additionally, bacterial endophyte that can fix nitrogen was studied with maize plant growth promotion under drought and low nitrogen stress conditions. The results suggested that diazotrophic bacterial endophyte can promote plant growth under moderate individual and combined stress conditions. Plant growth promoting endophytic bacteria can be utilized as an efficient tool to increase crop production under individual and concurrent abiotic stresses.
|
125 |
The effects of fertilization with bio-digester slurry and the inclusion of carbohydrate additives at ensiling on the nutritive value of Napier grass (pennisetum purpureum) silageRambau, Mashudu Daniel 05 1900 (has links)
MSCAGR (Animal Science) / Department of Animal Science / The objective of the study was to determine the effects of fertilisation with bio-digester slurry and
the inclusion of carbohydrate additives at ensiling on the fermentation characteristics, chemical
composition, ruminal degradability, and in vitro digestibility of Napier grass silage. Napier grass
planted at the School of Agriculture Experimental Farm, University of Venda in 5 m x 4 m plots
replicated three times in a completely randomised design and was irrigated with either biodigester
slurry or no bio-digester slurry (tap water) for a period of 12 weeks. After 12 weeks, the
Napier was freshly cut and ensiled for 90 days in 1 litre glass jars in a 2 (Control - tap water and
slurry irrigation) x 4 (No additive, molasses, maize meal and brown sugar) factorial arrangement.
Fermentation quality and nutritive composition were determined using standard protocols. The
dry matter (DM) and crude protein (CP) ruminal degradability was determined in sacco by
incubating feed samples in nylon bags (external dimension: 6 × 12 cm, pore size of 46 μm) in the
rumen in three Bonsmara steers fitted with rumen cannulae for 0, 6, 12, 24, 48, 72, 96 and 120
hours (h). Parameters to describe the dynamics of ruminal degradability of DM and CP were
obtained by fitting the data on the exponential equation P = a + b (1 - e-ct) using the NEWAY
computer program, where “a” is the rapidly degradable fraction, “b” is the slowly degradable
fraction and “c” is the outflow rate. The in vitro DM and CP degradability of rumen undegradable
residue collected after 12, 24 and 48 h incubation was determined by sequential digestion in
pepsin (abomasal) and pancreatin (small intestine) solutions. Fertilisation with bio-digester slurry
increased (P <0.05) CP content of fresh cut Napier grass pre-ensilage. Bio-digester slurry
fertilisation with molasses inclusion improved (P <0.05) the silage DM content which improved (P
>0.05) fermentation characteristics with pH of 4.2 and lowest NH3-N of 13.3 g/kg. Other chemical
compositions and fermentation characteristics were not affected (P >0.05) due to fertilisation x
additives treatment combinations. No bio-digester slurry fertilisation with maize meal inclusion
increased (P <0.01) DM degradability at 0 h incubation. As time progressed to 24 h, no biodigester
slurry fertilisation with no additive included reduced (P <0.01) DM degradability with no
difference (P >0.05) on other treatments. Potential DM degradability (a + b) of no bio-digester
slurry fertilisation with no additive inclusion silage was reduced (P <0.01). The reduction was
associated with low levels (P <0.01) of slowly degradable fraction “b”. In vitro DM and CP
digestibility were not affected (P >0.05) due to fertilisation x additives treatment combinations. In
conclusion, bio-digester slurry application improved the quality of fresh cut Napier grass, with the
combination of bio-digester slurry fertilisation and molasses addition yielding the best silage
quality.
|
Page generated in 0.0433 seconds