The evaluation of lupins (Lupinus angustifolius) as alternative protein source in ostrich (Struthio camelus var. domesticus) diets

Thesis (MScAgric)--Stellenbosch, 2016.

ENGLISH ABSTRACT: In an intensive ostrich production unit, one of the highest cost components is nutrition, contributing ca. 75% to the total input costs. Energy and protein are the two most important and abundant nutrients found in a balanced diet, with the protein component being the most expensive per unit weight. This study was conducted to evaluate the inclusion of lupins (Lupinus angustifolius) as an alternative protein source to soybean oilcake meal in ostrich (Struthio camelus var. domesticus) diets. In the first study (chapter 3) production performance and slaughter traits were studied at different dietary lupin inclusion levels that replaced soybean oilcake meal. There were five dietary treatments with three replications of between 15 – 17 chicks each. The chicks all received the same pre-starter diet. Five iso-nutritional diets were formulated for each feeding phase (starter, grower and finisher) using Mixit2+ software according to specifications set out for each of the different feeding phases Within each feeding phase these diets contained either soybean oilcake meal (control diet; 0LD) or sweet lupins (alternative protein source; diets 25LD, 50LD, 75LD and 100LD) as the primary protein source. The 100 lupin diet (LD) was formulated to include the maximum amount of sweet lupins according to the specifications for the specific species and the feeding phase. The maximum amount of lupins included in the 100LD therefore differs between the three feeding phases. The remaining three diets were formulated by mixing the diets to determine the gradual increase in lupins in the diets from 0LD up to 100LD. Soybean oilcake meal was thus gradually replaced by sweet lupins in the following ratios: 100:0 (0LD), 75:25 (25LD), 50:50 (50LD), 25:75 (75LD) and 0:100 (100LD) to make up the five dietary treatments for each feeding phase. No differences were found in the live weight of the birds at the end of each feeding phase or in the dry matter intake (DMI), average daily gain (ADG) or feed conversion ratio (FCR). The end weight (P = 0.07) and ADG (P = 0.09) for the starter phase tended to be higher for the birds on the 75LD. Birds fed the 50LD and 75LD tended (P = 0.08) to have the heaviest cold carcass weights, although dressing percentages did not differ. Birds receiving the 50LD diet had somewhat heavier (P = 0.05) thighs than those on the other diets. No differences were found for the weight of the big drum muscles of the birds. It was concluded that soybean oilcake meal can be replaced by sweet lupins in starter diets by up to 15% lupin inclusion in the diet (75LD) and in grower and finisher diets by up to 30% lupin inclusion in diet (100LD) without any significant detrimental effect on the production and slaughter traits. The second study (chapter 4) evaluated the three primary ostrich products (leather, meat and feathers) to clarify whether the lupin inclusion levels had any effect on these products. Birds used in this study were the same birds as described in chapter 1. No differences were found for the marketable feather classes and measured leather traits, but the leather was thicker (P < 0.05) for birds fed the 25LD. This corresponds with the heavier slaughter weight of the birds on the 25LD, although this was not significant. No differences were found in the chemical composition of the meat, apart from a higher (P < 0.05) intra-muscular fat content being found for birds on the 50LD. It can be concluded that the sweet lupin inclusion levels evaluated in this study had little influence on the leather traits, chemical composition of the meat of the birds measured (ten birds per treatment were selected around the median for chemical analysis of their meat) and the feather classes. In the third study (chapter 5), 60 South African Black growing ostriches were randomly divided into 10 paddocks with six birds per paddock. Three trials with five experimental diets per trial were conducted to investigate the effect of sweet and/or bitter lupins on the feed preference of growing ostriches in a free-choice system. In Trial 1 (sweet) and Trial 2 (bitter), lupins replaced soybean oilcake meal in a step-wise manner for inclusion levels of 0%, 7.5%, 15%, 22.5% and 30%. In Trial 3, the soybean oilcake meal was replaced with 0%, 15% sweet, 15% bitter, 30% sweet and 30% bitter lupin inclusion levels. The position of the feeders containing each diet in successive paddocks changed by rotating the five feed troughs in a clockwise direction, but within each paddock the specific position of each feeder and diet stayed the same throughout the three trials. No interaction was found between day and diet for the three trials. The DMI per diet did not differ between the five treatments in any of the three trials. However, in trial 2 the birds showed a tendency (P = 0.11) to prefer the 7.5% bitter lupin diet to the 15% and 30% diets. The results showed that soybean oilcake meal can be replaced in the diets of growing ostriches by sweet lupin inclusion of up to 30% without any significant detrimental effect on feed preference and intake. The tendency (P = 0.11) of the birds to discriminate to some extend against the 15% and 30% bitter lupin diets may warrant further research. This study found that lupins can be used without compromising growth or product quality in ostriches, making them a viable economic alternative.

AFRIKAANS OPSOMMING: Een van die grootste uitgawes van 'n volstruisproduksie-eenheid is die voedingskostes wat ongeveer 75% tot die totale insetkostes bydra. Energie en proteïen is die twee belangrikste en volopste voedingstowwe in 'n gebalanseerde volstruisrantsoen en tussen die twee is die proteïenkomponent die duurste per eenheid gewig. Hierdie studie is dus onderneem om die insluiting van lupiene (Lupinus angustifolius) as 'n alternatiewe proteïenbron in volstruisrantstoene (Struthio camelus var. domesticus) te evalueer. In die eerste studie (hoofstuk 3) was daar vyf diëte met drie herhalings van tussen 15 – 17 kuikens elk. Die kuikens het almal dieselfde voor-aanvangs dieët ontvang. Vyf diëte is daarna geformuleer met behulp van 'n rekenaargebaseerde program (Mixit2+) vir elke produksiestadium (aanvangs, groei en afronding) na aanleiding van spesifikasies soos uiteen gesit vir elk van die verskillende voedingsfases. Binne elke voedingsfase het die diëte of sojaboon oliekoekmeel (kontrole dieët, 0LD) of soetlupiene (alternatiewe proteïenbron, diëte 25LD, 50LD, 75LD en 100LD) as die primêre proteïenbron bevat. Die 100 lupien dieët (LD) was geformuleer om die maksimum hoeveelheid soetlupiene in te sluit, na aanleiding van die spesifikasies vir die spesifieke spesie en voedingsfase. Die maksimum hoeveelheid lupiene wat in die 100LD ingesluit is verskil dus tussen die drie voedingsfases. Die oorblywende drie diëte was geformuleer deur die diëte te meng om sodoende die geleidelike toename in lupiene van die diëte vanaf 0LD tot en met die 100LD te bepaal. Sojaboon oliekoekmeel was dus geleidelik vervang met soetlupiene in die volgende verhoudings: 100:0 (0LD), 75:25 (25LD), 50:50 (50LD), 25:75 (75LD) en 0:100 (100LD) om sodiende die vyf dieëtbehandelings vir elke voedingsfase te bepaal. Geen verskille is gevind in die lewendige gewig van die voëls aan die einde van elke voedingfase of in die droë materiaal inname (DMI), gemiddelde daaglikse toename (GDT) of voeromsetverhouding (VOV) nie. Die eindmassa (P = 0.07) en GDT (P = 0.09) vir die aanvangsfase het geneig om hoër te wees vir die voëls wat die 75LD ontvang het. Die voëls wat van die 50LD en 75LD ontvang het, het geneig (P = 0.08) om die swaarste koue karkasgewig te hê, alhoewel die uitslagpersentasie nie verskil het nie. Die voëls wat die 50LD ontvang het, het iewat (P = 0.05) swaarder dye gehad as die voëls op die ander diëte. Daar was ook geen verskille vir die gewig van die Muscularis gastrocnemius spiere van die voëls gevind nie. Daar is tot die gevolgtrekking gekom dat aanvangsdiëte tot en met 15% (75LD) soetlupiene kan bevat en groei- en afrondingsdiëte onderskeidelik tot en met 30% (100LD) soetlupiene kan bevat sonder enige betekenisvolle nadelige uitwerking op die produksie- en slageienskappe. Tydens die tweede studie (hoofstuk 4) is die drie primêre volstruisprodukte (leer, vleis en vere), wat vanaf die volstruise in die eerste studie (hoofstuk 1) geoes is, geëvalueer om te bepaal of die lupien-insluitingsvlakke hierdie eind-produkte geaffekteer het. Geen verskille is vir die bemarkbare vereklasse en vir die leereienskappe wat geëvalueer is gevind nie, maar die leer van die voëls wat die 25LD ontvang het was dikker (P < 0.05). Hierdie bevinding is in ooreenstemming met die swaarder slaggewig van die voëls wat die 25LD ontvang het, alhoewel dit nie betekenisvol was nie. Geen verskille is vir die chemiese samestelling van die vleis gevind nie, buiten vir die hoër binnespierse (P < 0.05) vetinhoud wat gevind is by die voëls wat die 50LD ontvang het. Ter opsomming is daar gevind dat die insluitingsvlakke van soetlupiene wat in hierdie studie getoets is 'n baie klein invloed op die leereienskappe, chemiese samestelling van die vleis van die geselekteerde voëls (tien voëls per behandeling is rondom die median geselekteer vir verdere chemiese analises van die vleis) en die onderskeie vereklasse gehad het. In die derde studie (hoofstuk 5) is 60 Suid-Afrikaanse volstruise lukraak in 10 kampe met ses voëls per kamp ingedeel. Drie proewe met vyf eksperiementele diëte per proef is uitgevoer om die voorkeur van groeiende volstruise ten opsigte van soet- en/of bitterlupiene in „n vrye-keuse stelsel te evalueer. In die eerste (soet) en tweede (bitter) proef het lupien-bevattende diëte sojaboon oliekoekmeel diëte met die volgende insluitingsvlakke in 'n stapsgewyse manier vervang: 0%, 7.5%, 15%, 22.5% en 30% lupiene in die dieët. Tydens die derde proef, was die sojaboon oliekoekmeel verplaas met 0%, 15% soet, 15% bitter, 30% soet en 30% bitterlupien-insluitingsvlakke in die dieët. Die posisie van die voerbakke wat elke dieët bevat het, het in die opeenvolgende kampe van mekaar verskil deur die volgorde van die vyf diëte in 'n kolksgewyse rigting te roteer, maar binne elke kamp het die spesifieke posisie van elke voerbak en dieët dieselfde gebly vir al drie proewe. Daar was geen interaksie tussen dag en dieët vir al drie die proewe gevind nie. Die DMI per dieët het nie verskil tussen die vyf behandelings in enige van die drie proewe nie. Tydens die tweede proef het die voëls egter „n neging (P = 0.11) getoon om 'n voorkeur te hê vir die 7.5% bitterlupien-dieët en het tot 'n mate gediskrimineer teen die 15% en 30% diëte met bitterlupiene. Vanuit die resultate kan daar tot die gevolgtrekking gekom word dat sojaboon oliekoekmeel in die diëte van groeivolstruise vervang kan word met soetlupien-insluitingsvlakke tot en met 30% sonder enige betekenisvolle nadelige effek op dieët-voorkeur en voerinname. Die neiging (P = 0.11) van voëls om teen die 15% en 30% bitterlupien-diëte te diskrimineer behoort verder ondersoek te word. Hierdie studie het dus bevind dat lupiene gebruik kan word in volstruisdiëte sonder om die groeipotensiaal of kwaliteit van enige van die drie volstruis-eindprodukte nadelig te beïnvloed, wat lupiene 'n lewensvatbare ekonomiese alternatiewe proteïenbron in volstruisdiëte maak.