猪胸膜肺炎放线杆菌生物被膜形成与抑制机制的研究

猪胸膜肺炎放线杆菌(App)引起猪的慢性呼吸道感染,给养猪业造成重大的经济损失。细菌生物被膜(BBF)是细菌为适应自然环境,吸附于生物材料或机体腔道表面保护细菌逃逸形成的细菌群落,由此引起的相关感染性疾病及慢性感染的反复发作称为细菌生物被膜病。App生物被膜(BF)属于菌体外具有空间结构的聚合物,其形成受多种基因调控,其中多药耐药外排泵和Ⅰ型分泌系统关键成分TolC基因缺失导致AppBF黏附减弱;Clp蛋白水解复合物的催化核心ClpP基因缺失引起BF形成受到抑制;App外膜脂蛋白VacJ促进BF的形成;活性酶LuxS基因缺失显示增强AppBF的形成,并减少细菌黏附能力;Adh基因缺失明显降低细菌的积聚、BF形成和对宿主细胞黏附。文章从分子水平上阐述AppBF形成或抑制机制,为探讨防制其生物被膜病提供参考依据。     

桃柁酚对金黄色葡萄球菌生物膜形成及cidA表达的影响

为研究桃柁酚对金黄色葡萄球菌(S.aureus)生物膜形成的影响及其机制,本研究通过结晶紫半定量法和激光共聚焦显微镜检测桃柁酚对S.aureus生物膜形成的影响,利用实时定量RT-PCR分析桃柁酚对cidA及其调控基因的作用,并测定了桃柁酚对胞外DNA (eDNA)释放的作用及对HaCaT细胞的细胞毒性.结果表明,桃柁酚可以有效减少eDNA的释放并抑制S.aureus生物膜的形成,并且抑制趋势呈剂量依赖关系.此外,在1/8×MIC药物浓度时,桃柁酚可以诱导eDNA的释放并诱导生物膜形成.桃柁酚可以通过影响agr和sar调控系统,作用于cidA基因进而影响eDNA释放及生物被膜的形成.而且,4×MIC浓度的桃柁酚对人体无毒害作用.本研究为治疗S.aureus感染提供新的方法,并为进一步研究桃柁酚的作用机制奠定了基础.     

几件重要动物病原菌生物被膜形成的研究进展

细菌生物被膜是指由于单一或多种类群细菌为了适应周围环境,由自身产生的多聚基质包围而形成,吸附于异物或组织表面,具有三维立体结构的膜样物,是细菌微菌落聚集体。生物被膜保护着细菌得以在恶劣环境中存活生长,较之浮游细菌,其更能抵抗宿主的免疫反应、抗生素及消毒剂的攻击。目前致病菌生物被膜形成在兽医学上的重要性极少受到关注,本文对细菌生物被膜的基础知识及动物重要病原菌已做的研究作一综述,旨在阐明病原菌形成生物被膜的机理,更加重视细菌生物被膜状态在动物疾病中的重要作用,并针对细菌生物被膜形成过程中重要的关键基因设计新型药物。     

纳米银抗菌及抗生物被膜机制研究进展

细菌耐药性及生物被膜感染问题一直备受关注，抗生素的使用不当或滥用导致了细菌耐药性越来越严重，一些细菌出现了多重耐药甚至超级耐药的情况。为了抵抗宿主的免疫反应及抗菌药物的攻击，细菌聚集后会形成生物被膜。生物被膜的形成进一步加强细菌的耐药性，生物被膜感染是细菌性疾病迁延不愈的重要原因之一。寻找广谱、高效的抗菌和抗生物被膜的抗生素替代物是目前的研究热点。纳米银(silver nanoparticles, AgNPs)由于自身的物理、化学和生物学特性，在抗菌及抗生物被膜方面受到广泛的关注，其抗菌机制主要包括了破坏细胞壁和细胞膜、DNA损伤、氧化应激等，抗生物被膜机制主要包括抑制相关基因的表达、抑制聚集黏附、阻断群体感应等。论文综述了纳米银抗菌及抗生物被膜的研究进展，以期为开发新型抗菌药物提供参考。     

细菌生物被膜耐药机制研究进展

生物被膜(Bf)是指附着于有生命或无生命物体表面,被一些大分子包裹的有组织的细菌群体,它富含多糖、多肽和磷脂等有机成分,极大地增加了细菌对抗菌药物的耐药性,可引起人和动物感染。目前,防止感染策略是阻止微生物被膜菌落附着在物体表面,这将有助于改善临床严重传染病的治疗效果。此外,鉴别并抑制生物被膜形成基因也是控制此类感染的重要研究方向。文章对引起普遍关注的细菌生物被膜耐药性的分子机制进行综述。     

鱼腥草素钠对金黄色葡萄球菌生物被膜的抑制作用

为了研究鱼腥草素钠对金黄色葡萄球菌(S.aureus)生物被膜的抑制活性,试验采用微量稀释法考察了鱼腥草素钠对S.aureus浮游菌的最小抑菌浓度(MIC)和最小杀菌浓度(MBC),用琼脂平板法测定了其对生物被膜的最小抑膜浓度(MBIC)和最小杀膜浓度(MBBC);通过激光共聚焦显微镜考察了鱼腥草素钠对生物被膜的清除能力;通过Western-blot考察了鱼腥草素钠对S.aureus毒力因子分泌的影响。结果表明:鱼腥草素钠对浮游菌有很好的抑制作用(MIC、MBC:16~64μg/mL),对成熟的生物被膜没有明显的抑制作用(MBIC、MBBC1 024μg/mL),但其亚抑菌浓度在生物被膜形成早期有显著抑制作用,并呈剂量依赖抑制α-溶血素、肠毒素A和肠毒素B的分泌。说明鱼腥草素钠对金黄色葡萄球菌浮游菌和早期生物被膜有较好抑制活性。     

生物被膜的形成过程及耐药机制

细菌生物被膜（Bacterial Biofilm,BBF）是临床常见感染的主要致病原,可导致感染迁延不愈和反复急性发作。由于细菌生物被膜可以保护细菌抵御抗菌药物的杀伤和逃逸宿主的免疫,导致临床相关感染的难治性。所以,BBF耐药屏障的研究已成为国外医学、药学、微生物学专家关注的重要课题。     

大环内酯类抗生素对细菌生物被膜作用的研究进展

细菌生物被膜(BBF)是一类由生物大分子包裹细菌而形成的具有特殊复杂结构的微克隆多细胞群体,由其感染所引起的疾病具有迁延不愈、反复发作等特点,在临床上有较大危害性。当前临床上用于治疗细菌生物被膜疾病的药物主要集中于大环内酯类抗生素,文章综述了细菌生物被膜结构特点和大环内酯类抗生素的药效动力学,并将大环内酯类抗生素清除、抑制细菌生物被膜的主要机理归纳为阻碍细菌黏附过程、破坏细菌生物被膜基础结构和干扰细菌的群体感应系统。     

盐酸血竭素对金黄色葡萄球菌分选酶A活性影响研究

为探究盐酸血竭素(DP)抗金黄色葡萄球菌(S.aureus)分选酶A(SrtA)的活性及机制,本研究利用纤连蛋白黏附试验和细胞侵袭试验,验证DP通过抑制SrtA的活性影响S.aureus黏附于纤连蛋白和降低其对细胞的侵袭能力;利用荧光底物肽实验,测定DP对S.aureus SrtA的抑制作用;利用生物膜试验,观察DP对S.aureus形成生物被膜(BF)的影响能力;利用分子模拟和定点突变方法,分析验证DP对SrtA的活性中心影响作用。结果表明,DP分别在2μg/mL、4μg/mL、8μg/mL和16μg/mL时,可显著性抑制S.aureus SrtA蛋白的催化活性,且这一抑制作用呈浓度依赖性;DP可以通过影响SrtA的催化活性从而阻碍其表面蛋白锚定于宿主细胞表面,进而降低S.aureus侵袭细胞的能力;DP在8μg/mL和16μg/mL时可以显著降低S.aureus与纤连蛋白结合的能力(p<0.01);DP在2μg/mL、4μg/mL、8μg/mL和16μg/mL时均可以显著降低S.aureus形成BF的能力;DP可通过与SrtAΔN59中的P30和T105结合而封闭了其活性中心。综上所述,DP可作用于S.aureus毒力因子SrtA,通过抑制SrtA的活性达到减弱其毒力的效果。本研究将为DP抗S.aureus的作用机制提供参考依据。     

防控细菌生物被膜的新武器——噬菌体

细菌生物被膜(bacterial biofilms)是由细菌互相粘连、不可逆地固着于生物机体或物体表面并由细菌分泌的胞外基质包裹的微生物群落。生物被膜为细菌提供了一种保护性生活方式,其形成有利于微生物持续定植,抵抗宿主免疫系统清除,提高对抗生素的耐受性以及遗传物质的交换。细菌生物被膜的存在对生物医学、食品加工等方面极为不利,因此,迫切需要研发能够去除生物被膜的新技术。目前,噬菌体被认为是控制生物被膜的一种有效方法。本文综述了应用噬菌体防控生物被膜的最新进展。     

Plasma pharmacokinetics and milk levels of ceftriaxone following single intravenous administration in healthy and endometritic cows

Pharmacokinetics and milk levels of ceftriaxone were studied in healthy and endometritic cows following single intravenous administration. The drug was detected up to 8 h of dosing in plasma of healthy and endometritic cows and the drug disposition followed three-compartment open model. The values of Vd_area, AUC, t_1/2β, Cl_B, MRT and P/C ratio were 0.50 ± 0.19 L.kg⁻¹, 62.2 ± 23.3 μg.ml⁻¹.h, 1.02 ± 0.07 h, 0.30 ± 0.09 L.kg⁻¹.h⁻¹, 1.55 ± 0.25 h and 0.52 ± 0.27, respectively, in healthy and 1.55 ± 0.52 L.kg⁻¹, 37.0 ± 17.1 μg.ml⁻¹.h, 1.56 ± 0.25 h, 0.56 ± 0.14 L.kg⁻¹.h⁻¹, 2.14 ± 0.34 h and 1.44 ± 0.60, respectively, in endometritic cows. The drug was detected in milk for 36 h after administration. For MIC₉₀ of 0.5 μg.ml⁻¹ the most appropriate dosage for ceftriaxone, would be 9.0 mg.kg⁻¹ repeated at 6 h intervals for the treatment of endometritis in cows.     

Early resynchronization protocols for goats: Progestogens can be used prior to an early pregnancy diagnosis without affecting corpus luteum functionality

This study aimed to evaluate the exogenous progesterone (P4) effect on the luteal function from Day 16 to Day 21 of the oestrous cycle in inseminated goats with unknown pregnancy status. A total of 54 does passed through a short progestin-based synchronization protocol and, on Day 16 of the following oestrous cycle, 27 does received a new P4 device which was retained until Day 21. Blood samples were collected daily from all does during this period, as well as on Day 24. Pregnancy diagnoses were performed on Day 30. Serum P4 values from 26 animals (G_NPSP: Group of non-pregnant does with second sponge: n = 8; G_NPNSP: Group of non-pregnant does without second sponge: n = 6; G_PSP: Group of pregnant does with second sponge: n = 5; G_PNSP: Group of pregnant does without second sponge: n = 7) were determined by radioimmunoassay commercial kits. No P4 differences were found between groups (G_NPSP: 3.1 ± 2.8; 1.7 ± 1.8; 0.4 ± 1.0; and 0.0 ± 0.0 vs. G_NPNSP: 4.4 ± 1.8; 3.0 ± 2.2; 0.8 ± 0.8; and 0.0 ± 0.0 or G_PSP: 4.2 ± 1.0; 3.4 ± 0.6; 3.3 ± 1.6; 3.2 ± 0.9; 3.6 ± 1.2; 3.5 ± 1.3; 2.7 ± 1.3 vs. G_PNSP: 4.4 ± 1.6; 3.6 ± 1.5; 3.7 ± 1.5; 3.8 ± 1.4; 3.2 ± 1.2; 3.1 ± 1.2; 3.6 ± 1.1; D16, D17, D18, D19, D20, D21, D24, respectively) or for the interaction of group and time. In conclusion, a second progestogen device had no effect on luteolysis or early pregnancy in the following oestrous cycle.     

Ovarian activity in F1 prepubertal ewe lambs under tropical conditions

Seventy crossbred ewe lambs, born from Pelibuey (PB) dams mated with five sire breeds: White Dorper × PB (WD × PB), Black Head Dorper × PB (BHD × PB), Ile de France × PB (Ile × PB) Katahdin × PB (KT × PB) and Pelibuey (PB × PB), were used to determine age and weight to puberty, follicular populations during prepubertal development, ovulation rate at first ovulation and function of the first corpus luteum (FCL). Ewe lambs were maintained under grazing conditions and were supplemented with 300 g head^− 1 day^− 1 of a concentrate with 14% CP and 3.0 Mcal ME kg^− 1 of DM. From 145 days of age, monthly observations were performed by endoscopy to monitor follicular populations and luteal structures. Ovarian follicles were classified according to size into small (≥ 1 and < 3 mm), medium (≥ 3 and ≤ 4 mm) and large (> 4 mm). Additionally, weekly observations by ultrasonography were performed in four ewes per genotype to assess follicular populations. Luteal function from first ovulation was determined by circulating concentrations of progesterone. Ovulation rate was not affected by genotype (P > 0.05). All breed groups had the same pattern of follicular populations, where most of follicles were small, followed by medium and a small proportion of large follicles. Maximum diameter of follicles was similar for all genotypes during prepubertal development (P > 0.05), with an average range of 3.9 ± 0.20 to 4.4 ± 0.20 mm. The BHD × PB reached puberty at the youngest age of 240.9 ± 13.0 days, compared to all other genotypes (P < 0.05), 259.1 ± 11.7 for WD × PB, 279.3 ± 9.6 for KT × PB and 289.0 ± 15.3 days for PB × PB and 308.6 ± 11.9 days for Ile × PB ewe lambs. Ile × PB had greater weight to first ovulation (31.5 ± 1.19 kg) as compared to other breed groups (P < 0.01). The largest percentage of FCL was for KT × PB ewes (100%) (P < 0.05), followed by BHD × PB (88.9%), PB × PB (83.3), WD × PB (78.6%) and Ile × PB (77.8%). There were no differences in ovulation rate attributable to type of lambing from which ewe lambs came from (P > 0.05). BHD × PB ewe lambs reached puberty at an earlier age than other in this study. KT × PB ewe lambs had the highest percentage of FCL in their first ovulation. Breed of sire Ile de France increased weight to puberty and decreased FCL at first ovulation. In conclusion, the BHD × PB ewe showed puberty at an earlier age than other genotypes, while the KT × PB had the highest percentage of functional corpus luteum in their first ovulation. Ewe lambs coming from single lambings reach puberty at a heavier weight than those coming from multiple lambings. The ovulation rate in the first ovulation of ewe lambs is not affected by genotype and type of lambing.     

Influence of dietary lysine level on whole-body protein turnover, plasma IGF-I, GH and insulin concentration in growing pigs

Four growing pigs (initial liveweight 25.9 ± 0.54 kg, final liveweight 43.0 ± 1.06 kg) were used to study the effect of dietary lysine level on nutrient digestibility, whole-body protein turnover, plasma insulin-like growth factor-I (IGF-I), growth hormone (GH), insulin, glucose, and urea nitrogen (PUN). Four diets, containing 7.0 g (L1), 9.5 g (L2), 12.0 g (L3) and 14.5 g (L4) lysine per kg diet respectively, were formulated as experimental treatments. The animals and diets were allocated in a 4 × 4 Latin square design. Nitrogen (N) metabolism and whole-body protein turnover were measured by classical method and single-dose ¹⁵N end-product method, respectively. The blood samples were taken at the end of each experimental period. Results showed that N retention (NR) and N biological value (NBV) were significantly increased from L1 to L4 (P < 0.05). However, differences in NR and NBV between L2, L3 and L4 were not significant (P > 0.05). There was no significant difference on dry matter (DM) digestibility, organic matter (OM) digestibility and N digestibility between different treatments (P > 0.05). Whole-body protein synthesis, protein degradation and protein accretion increased markedly from L1 to L2 (P < 0.05), but did not increase further from L2 to L4. Whole-body protein accretion (y, g/kg W^0.75/d) increased with dietary lysine (x, g/kg) in a quadratic manner: y = − 0.09x² + 2.12x − 5.14 (r² = 0.96, n = 4, P < 0.05).The results also showed that differences in plasma IGF-I, GH, glucose and PUN concentration between different treatments were not significant (P > 0.05). Plasma insulin concentration (y, μIU/ml) was increased with dietary lysine (x, g/kg) in a quadratic manner: y = 0.23x² − 4.10x + 32.25 (r² = 0.99, n = 4, P < 0.05), but it was not found that plasma insulin concentration was related to NR. A significant correlation was found between NR (y, g/d) and plasma IGF-I (x, ng/ml): y = − 3.1 × 10^− 3x² + 1.31x − 122.28 (r² = 0.99, n = 4, P < 0.05).It was concluded that dietary lysine level had a significant influence on NR and whole-body protein turnover but not on plasma IGF-I and GH concentration. Plasma IGF-I may be an important factor controlling N metabolism of growing pigs. Further research was needed to study the mechanism.     

Pharmacokinetics,plasma protein binding and bioavailability of moxifloxacin in Muscovy ducks after different routes of administration

In this study the disposition kinetics and plasma availability of moxifloxacin in Muscovy ducks after single intravenous (i.v.), intramuscular (i.m.) and oral (p.o.) administrations of 5 mg kg^?1 b.wt. were investigated. The concentrations of moxifloxacin in the plasma were measured using high-performance liquid chromatography (HPLC) with fluorescence detection on samples collected at frequent intervals after drug administration. Following intravenous injection, the decline in plasma drug concentration was bi-exponential with half-lives of (t_1/2α) 0.22 ± 0.10 h and (t_1/2β) 2.49 ± 0.26 h for distribution and elimination phases, respectively. The volume of distribution at steady-state (V_dss) was 1.02 ± 0.14 l kg^?1 and the total body clearance (Cl_tot) was 0.32 ± 0.11 l kg^?1 h^?1, respectively. After intramuscular and oral administration of moxifloxacin at the same dose the peak plasma concentrations (C_max) were 2.38 ± 0.43 and 2.11 ± 0.36 μg ml^?1 and were obtained at 1.47 ± 0.26 and 1.83 ± 0.16 h (T_max), respectively, the elimination half-lives (T_1/2el) were 3.14 ± 0.42 and 2.63 ± 0.44 h, respectively, and AUC_0–24 were 15.87 ± 2.35 and 14.52 ± 2.37 μg ml^?1 h^?1, respectively. The systemic bioavailabilities were 96.36 ± 11.54% and 86.79 ± 12.64%, respectively. In vitro plasma protein binding percent was 32%. We concluded that moxifloxacin might be clinically interesting alternative for the treatment of most sensitive bacterial infections in Muscovy ducks.     

Leptospirosis in Colombia: Isolation ofLeptospira SPP. from the kidneys of brown rats (Rattus Norvegicus) trapped on infected piggeries

Summary Leptospira interrogansserotypes pomonaand icterohaemorrhagiaewere isolated from the kidneys of Rattus norvegicustrapped on pomonainfected piggeries.The isolation of pomonafrom one of 111cultured kidneys, although of interest, strongly suggests that this rat does not play an important part in the epidemiology of infection by this serotype. Kidney tubular degeneration, focal mononuclear infiltrations and fibroplasia are morphological traces which remain after an attack of leptospirosis. The high percentage (48.6)of these lesions found in the rat kidneys examined does not seem to be related to serotype pomonabut to icterohaemorrhagiae.The importance of this last serotype in swine in the Cauca Valley has yet to be assessed.

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Leptospirosis En Colombia: Aislamiento DeLeptospira SPP. De Riñones De Ratas Pardas (Rattus Norvegicus) Atrapadas En Porquerizas Infectadas

Resumen Se aislóLeptospira interrogans serotipospomona eicterohaemorrhagiae de riñones deRattus norvegicus atrapadas en porquerizas infectadas porpomona. El aislamiento depomona de 1/111 riñones cultivados, aunque de interés, sugiere que esta rata no desempeña parte importante en la epidemiología de las infecciones por este serotipo.Degeneración tubular renal, infiltración mononuclear focal y fibroplasia son huellas morfológicas que quedan después de un ataque de leptospirosis. El alto porcentaje (48.6) de estas lesiones encontradas en los riñones de las ratas examinadas no parece estar relacionado con el serotipopomona sino con elicterohaemorrhagiae. La importancia de este último seroptipo en cerdos en el Valle del Cauca no se ha evaluado todavía.

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Leptospiroses En Colombie: Isolement DeLeptospira SPP. De Reins De Rats Bruns (Rattus Norvegicus) Captures Dans Des Porcheries

Résumé Les sérotypespomona eticterohaemorrhagiae deLeptospira interrogans ont été isolés de reins deRattus norvegicus capturés dans des porcheries infectées de (pomona?). L'isolement depomona sur une seule des 111 cultures de rein effectuées, bien qu'interessant, suggère fortement que ce rat ne joue pas un rôle important dans l'épidémiologie de l'infection par ce sérotype.La dégénerescence tubulaire des reins, des infiltrations ponctuelles par des monocucléaires et l'aspect fibreux constituent les traces morphologiques qui demeurent après une attaque de leptospirose. Le pourcentage élevé (48,6) de ces lésions trouvées dans les les reins des rats examinés semble être plus en rapport avec le sérotypeicterohaemorrhagiae qu'avec le sérotypepomona. L'importance du sérotypeicterohaemorrhagiae chez le porc de la Cauca Valley est encore à vérifier.

     

Filarial infection of equidae in the Tehran area of Iran

Summary Microfilariae of three genera, namelyElaeophora böhmi, Onchocerca cervicalis andParafilaria multipapillosa were recovered from blood samples of equidae in Tehran, Iran. These microfilarial infections in equidae are reported for the first time from Iran.

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Infestacion Filaroidea De Equinos En El Area De Teheran, Iran

Resumen Microfilarias de tres géneros,Elaeophora bohmi, Onchocerca cervicalis andParafilaria multipapillosa se aislaron de la sangre de equinos en el area de Teherán, Irán. Este es el primer reporte de la infestación filaroidea de equinos en Irán.

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Filariose Des Equides Dans La Region De Teheran En Iran

Résumé Les microfilaires des genresElaeophora böhmi, Onchocerca cervalis etParafilaria multipapillosa ont été trouvées dans des échantillons de sang d'équidés de la région de Téhéran en Iran. C'est la première fois qu'un tel parasitisme des équidés est constaté en Iran.

     

Serological prevalence of bovine babesiosis in Mali

Summary A serological survey of cattle in Mali was carried out to determine the prevalence of antibody activity toBabesia bovis andB. bigemina. It was found that the level ofB. bovis infection as indicated by antibody activities was too low to be of immediate concern. However, the serological prevalence ofB. bigemina was high and this may indicate a potential disease problem. It was also found that when zebu and N'Dama cattle grazed together the N'Dama were twice as likely to have positive titres toBabesia as were the zebus.

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Prevalencia Serologica De Babesiosis Bovina En Mali

Resumen Se llevó a cabo un análisis serológico en Malí, para detectar la prevalencia deBabesia bovis yBabesia bigemina. Se encontró, que la prevalencia serológica deB. bovis es baja para considerar la enfermedad una amenaza inmediata. Sinembargo, la prevalencia deB. bigemina fué alta, un problema potencial. Tambien se encontró, que cuando el ganado Cebu y N'Dama pastorea junto, el N'Dama presenta el doble de títulos serológicos deB. bigemina.

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Frequence Serologique De La Babesiose Bovine Au Mali

Résumé Une enquête sérologique sur le bétail au Mali a été effectuée pour déterminer la fréquence de l'activité des anticorps àBabesia bovis etB. bigemina. On a trouvé que le degré d'infection àB. bovis tel qu'indiqué par les réactions anticorps était trop faible pour constituer un souci immédiat. Cependant la fréquence sérologique deB. bigemina était élevée, ce qui peut indiquer un problème pathologique potentiel. On a aussi noté que lorsque les zébus et les N'Dama broûtaient ensemble, les N'Dama avaient deux fois plus de chance d'avoir des titres positifs àBabesia que ne l'avaient les zébus.

     

Rumen degradation characteristics of sweet potato foliage and performance by local and crossbred calves fed milk and foliage from three cultivars

The study investigated rumen dry matter (DM) degradability characteristics in a completely randomized design and the effects of milk, sweet potato foliage (SPF) from three cultivars (A = TIS-87/0087; B = TIS-8164; C = TIS-2532.OP.1.13), dried brewers' grains (DBG) and cottonseed meal (CSM) as supplements to Panicum maximum (Panicum) for pre-weaned calves in randomized complete block designs. Diet 1 = milk + SPF-A foliage + Panicum, Diet 2 = milk + SPF-B foliage + Panicum, Diet 3 = milk + SPF-C foliage + Panicum, and Diet 4 = milk + DBG & CSM + Panicum (as control). Dry matter (130 ± 0.4 to 864 ± 3.9 g kg^− 1), ash (54 ± 4.2 to 173 ± 2.8 g kg^− 1 DM), OM (827 ± 4.2 to 946 ± 5.7 g kg^− 1 DM), N (7.4 ± 0.6 to 38.6 ± 1.4 g kg^− 1 DM), and NDF (439 ± 1.4 to 774 ± 8.5 g kg^− 1 DM) contents were highly significant (P < 0.01). In Trial I, 16 pre-weaned calves were used over 70 d with milk intake (34.8 ± 4.4 ml kg W^− 0.75 d^− 1), Panicum DMI (22.3 ± 2.77 g kg W^− 0.75 d^− 1), total DMI (35.7 ± 2.83 g kg W^− 0.75 d^− 1), and LWG (198 ± 44.6 g d^− 1) not significantly different (P > 0.05). Supplement DMI varied (P < 0.05) from 11.6 g kg W^− 0.75 d^− 1 in Diet 3 to 16.6 g kg W^− 0.75 d^− 1 in Diet 4. In Trial II, 16 pre-weaned local and crossbred calves were involved over 77 d with initial age of calves, Panicum intake, metabolic DMI, and LWG similar (P > 0.05) among crosses. Birthweight varied (P < 0.05) from 17.3 kg for N'Dama × Jersey crosses to 21.2 kg for White Fulani × Brown Swiss crosses. Supplement and total DMI ranged (P < 0.05) from 172 to 483 g d^− 1 for N'Dama × Jersey crosses to 233 and 674 g d^− 1 for non-inseminate or purebred calves, respectively. The LWG in the White Fulani × Brown Swiss and the N'Dama × Jersey calves were respectively 30% and 24% better, though not significantly, than purebred calves. In Trial III, rumen DM degradability characteristics of feeds in three N'Dama steers showed no significant differences (P > 0.05) in slowly degradable fraction (b) and rate of degradation of b (c). Soluble fraction (a), 48-h degradation, potential degradability (PD) and effective degradability (ED) varied significantly (P < 0.05) and were lowest in Panicum, but similar for foliage among the three sweet potato cultivars. Panicum fodder showed improvements in degradation characteristics with supplementation.